Effects of climate change on oceans: Difference between revisions

Content deleted Content added

Inline

Revision as of 14:08, 1 April 2022

The effects of climate change on oceans include the rise in sea level from ocean warming and ice sheet melting, and changes in pH value (ocean acidification), circulation, and stratification due to changing temperatures leading to changes in oxygen concentrations. There is clear evidence that the Earth is warming due to anthropogenic emissions of greenhouse gases and leading inevitably to ocean warming.^[1] The greenhouse gases taken up by the ocean (via carbon sequestration) help to mitigate climate change but lead to ocean acidification.

Physical effects of climate change on oceans include sea level rise which will in particular affect coastal areas, ocean currents, weather and the seafloor. Chemical effects include ocean acidification and reductions in oxygen levels. Furthermore, there will be effects on marine life. The consensus of many studies of coastal tide gauge records is that during the past century sea level has risen worldwide at an average rate of 1–2 mm/yr reflecting a net flux of heat into the surface of the land and oceans. The rate at which ocean acidification will occur may be influenced by the rate of surface ocean warming, because the chemical equilibria that govern seawater pH are temperature-dependent.^[2] Increase of water temperature will also have a devastating effect on different oceanic ecosystems like coral reefs. The direct effect is the coral bleaching of these reefs, which live within a narrow temperature margin, so a small increase in temperature would have a drastic effects in these environments.

Physical effects

Temperature rise and ocean heat content

From 1961 to 2003, the global ocean temperature has risen by 0.10 °C from the surface to a depth of 700 m.^[6] For example, the temperature of the Antarctic Southern Ocean rose by 0.17 °C (0.31 °F) between the 1950s and the 1980s, nearly twice the rate for the world's oceans as a whole.^[7] There is variability both year-to-year and over longer time scales, with global ocean heat content observations showing high rates of warming for 1991 to 2003, but some cooling from 2003 to 2007.^[6] Nevertheless, there is a strong trend during the period of reliable measurements.^[8] Increasing heat content in the ocean is also consistent with sea level rise, which is occurring mostly as a result of thermal expansion of the ocean water as it warms.^[8]

This uptake has accelerated in the 1993–2017 period compared to 1969–1993.^[9]^[10] The warming rate varies with depth: at a depth of a thousand metres the warming occurs at a rate of almost 0.4 °C per century (data from 1981 to 2019), whereas the warming rate at two kilometres depth is only half.^[11]

Sea level rise

Between 1901 and 2018, average global sea level rose by 15–25 cm (6–10 in), an average of 1–2 mm (0.039–0.079 in) per year.^[12] This rate accelerated to 4.62 mm (0.182 in)/yr for the decade 2013–2022.^[13] Climate change due to human activities is the main cause.^[14]^: 5, 8 Between 1993 and 2018, thermal expansion of water accounted for 42% of sea level rise. Melting temperate glaciers accounted for 21%, while polar glaciers in Greenland accounted for 15% and those in Antarctica for 8%.^[15]^: 1576

Sea level rise lags behind changes in the Earth's temperature, and sea level rise will therefore continue to accelerate between now and 2050 in response to warming that has already happened.^[16] What happens after that depends on human greenhouse gas emissions. Sea level rise would slow down between 2050 and 2100 if there are very deep cuts in emissions. It could then reach slightly over 30 cm (1 ft) from now by 2100. With high emissions it would accelerate. It could rise by 1.01 m (31⁄3 ft) or even 1.6 m (51⁄3 ft) by then.^[14]^[17]^: 1302 In the long run, sea level rise would amount to 2–3 m (7–10 ft) over the next 2000 years if warming amounts to 1.5 °C (2.7 °F). It would be 19–22 metres (62–72 ft) if warming peaks at 5 °C (9.0 °F).^[14]^: 21

Energy (heat) added to various parts of the climate system due to global warming.

Ocean currents

Ocean currents are caused by varying temperatures associated with sunlight and air temperatures at different latitudes, as well as by prevailing winds and the different densities of saline and fresh water.

Air tends to be warmed and thus rise near the equator, then cool and thus sink slightly further poleward. Near the poles, cool air sinks, but is warmed and rises as it travels along the surface equatorward. This creates large-scale wind patterns known as Hadley cells, with similar effects driving a mid-latitude cell in each hemisphere.^[18] Wind patterns associated with these circulation cells drive surface currents^[19] which push the surface water to the higher latitudes where the air is colder. This cools the water down enough to where it is capable of dissolving more gasses and minerals, causing it to become very dense in relation to lower latitude waters, which in turn causes it to sink to the bottom of the ocean, forming what is known as North Atlantic Deep Water (NADW) in the north and Antarctic Bottom Water (AABW) in the south.^[20] Driven by this sinking and the upwelling that occurs in lower latitudes, as well as the driving force of the winds on surface water, the ocean currents act to circulate water throughout the entire sea. When global warming is added into the equation, changes occur, especially in the regions where deep water is formed. With the warming of the oceans and subsequent melting of glaciers and the polar ice caps, more and more fresh water is released into the high latitude regions where deep water is formed. This extra water that gets thrown into the chemical mix dilutes the contents of the water arriving from lower latitudes, reducing the density of the surface water. Consequently, the water sinks more slowly than it normally would.^[21]

There is some concern that a slowdown or shutdown of the thermohaline circulation, trigger localized cooling in the North Atlantic and lead to cooling, or lesser warming, in that region.^[22] This would affect in particular areas like Scandinavia and Britain that are warmed by the North Atlantic drift. Lenton et al. found in 2008 that "simulations clearly pass a THC tipping point this century".^[22] IPCC (2007b:17) concluded that a slowing of the Meridional Overturning Circulation would very likely occur this century.^[23] Due to overall global warming, temperatures across the Atlantic and Europe were still projected to increase.

In 2021 scientists find signs of possible transition of the Atlantic meridional overturning circulation to the weak mode of circulation due to climate change in the next 10 – 50 years. The currents move in the slowest speed at the latest 1600 years. Such change will cause severe disasters by: "severely disrupting the rains that billions of people depend on for food in India, South America and West Africa; increasing storms and lowering temperatures in Europe; and pushing up the sea level off eastern North America. It would also further endanger the Amazon rainforest and Antarctic ice sheets".^[24]

It is important to note that ocean currents provide the necessary nutrients for life to sustain itself in the lower latitudes.^[25] Should the currents slow down, fewer nutrients would be brought to sustain ocean life resulting in a crumbling of the food chain and irreparable damage to the marine ecosystem. Slower currents would also mean less carbon fixation. Naturally, the ocean is the largest sink within which carbon is stored. When waters become saturated with carbon, excess carbon has nowhere to go, because the currents are not bringing up enough fresh water to fix the excess. This causes a rise in atmospheric carbon dioxide which in turn causes positive feedback that can lead to a runaway greenhouse effect.^[26]

Weather

Global warming also affects weather patterns as they pertain to cyclones. Scientists have found that although there have been fewer cyclones than in the past, the intensity of each cyclone has increased.^[27] A simplified definition of what global warming means for the planet is that colder regions would get warmer and warmer regions would get much warmer.^[28] However, there is also speculation that the complete opposite could be true. A warmer earth could serve to moderate temperatures worldwide. There is still much that is not understood about the earth's climate, because it is very difficult to make climate models. As such, predicting the effects that global warming might have on our planet is still an inexact science.^[29] Global warming is also causing the amount of hazards on the ocean to increase. It has increased the amount of fog at sea level, making it harder for ships to navigate without crashing into other boats or other objects in the ocean. The warmness and dampness of the ground is causing the fog to come closer to the surface level of the ocean. As the rain falls it makes the ground wet, then the warm air rises leaving a layer of cold air that turns into fog causing an unsafe ocean for travel and for working conditions on the ocean.^[30] It is also causing the ocean to create more floods due to the fact that it is warming up and the glaciers from the ice age are now melting causing the sea levels to rise, which causes the ocean to take over part of the land and beaches.^[31] Glaciers are melting at an alarming rate which is causing the ocean to rise faster than predicted. Inside of this ice there are traces of bubbles that are filled with CO₂ that are then released into the atmosphere when they melt causing the greenhouse effect to grow at an even faster rate.^[32]

Regional weather patterns across the globe are also changing due to tropical ocean warming. The Indo-Pacific warm pool has been warming rapidly and expanding during the recent decades, largely in response to increased carbon emissions from fossil fuel burning.^[33] The warm pool expanded to almost double its size, from an area of 22 million km² during 1900–1980, to an area of 40 million km² during 1981–2018.^[34] This expansion of the warm pool has altered global rainfall patterns, by changing the life cycle of the Madden Julian Oscillation (MJO), which is the most dominant mode of weather fluctuation originating in the tropics.

Seafloor

It is known that climate affects the ocean and the ocean affects the climate. Due to climate change, as the ocean gets warmer this too has an effect on the seafloor. Because of greenhouse gases such as carbon dioxide, this warming will have an effect on the bicarbonate buffer of the ocean. The bicarbonate buffer is the concentration of bicarbonate ions that keeps the ocean's acidity balanced within a pH range of 7.5–8.4.^[35] Addition of carbon dioxide to the ocean water makes the oceans more acidic. Increased ocean acidity is not good for the planktonic organisms that depend on calcium to form their shells. Calcium dissolves with very weak acids and any increase in the ocean's acidity will be destructive for the calcareous organisms. Increased ocean acidity will lead to decreased Calcite Compensation Depth (CCD), causing calcite to dissolve in shallower waters.^[35] This will then have a great effect on the calcareous ooze in the ocean, because the sediment itself would begin to dissolve.

If ocean temperatures rise it will have an effect right beneath the ocean floor and it will allow the addition of another greenhouse gas, methane gas. Methane gas has been found under methane hydrate, frozen methane and water, beneath the ocean floor. With the ocean warming, this methane hydrate will begin to melt and release methane gas, contributing to global warming.^[36] However, recent research has found that CO2 uptake outpaces methane release in these areas of the ocean causing overall decreases in global warming.^[37]

Chemical effects

Ocean acidification

Ocean acidification is the ongoing decrease in the pH of the Earth's ocean. Over the past 200 years, the rapid increase in anthropogenic CO₂ (carbon dioxide) production has led to an increase in the acidity of the Earth’s oceans. Between 1950 and 2020, the average pH of the ocean surface fell from approximately 8.15 to 8.05.^[38] Carbon dioxide emissions from human activities are the primary cause of ocean acidification, with atmospheric carbon dioxide (CO₂) levels exceeding 410 ppm (in 2020). CO₂ from the atmosphere is absorbed by the oceans. This chemical reaction produces carbonic acid (H₂CO₃) which dissociates into a bicarbonate ion (HCO−3) and a hydrogen ion (H⁺). The presence of free hydrogen ions (H⁺) lowers the pH of the ocean, increasing acidity (this does not mean that seawater is acidic yet; it is still alkaline, with a pH higher than 8). Marine calcifying organisms, such as mollusks and corals, are especially vulnerable because they rely on calcium carbonate to build shells and skeletons.^[39]

A change in pH by 0.1 represents a 26% increase in hydrogen ion concentration in the world's oceans (the pH scale is logarithmic, so a change of one in pH units is equivalent to a tenfold change in hydrogen ion concentration). Sea-surface pH and carbonate saturation states vary depending on ocean depth and location. Colder and higher latitude waters are capable of absorbing more CO₂. This can cause acidity to rise, lowering the pH and carbonate saturation levels in these areas. Other factors that influence the atmosphere-ocean CO₂ exchange, and thus local ocean acidification, include: ocean currents and upwelling zones, proximity to large continental rivers, sea ice coverage, and atmospheric exchange with nitrogen and sulfur from fossil fuel burning and agriculture.^[40]^[41]^[42]

Oxygen depletion

Ocean deoxygenation is the reduction of the oxygen content in different parts of the ocean due to human activities.^[43]^[44] There are two areas where this occurs. Firstly, it occurs in coastal zones where eutrophication has driven some quite rapid (in a few decades) declines in oxygen to very low levels.^[43] This type of ocean deoxygenation is also called dead zones. Secondly, ocean deoxygenation occurs also in the open ocean. In that part of the ocean, there is nowadays an ongoing reduction in oxygen levels. As a result, the naturally occurring low oxygen areas (so called oxygen minimum zones (OMZs)) are now expanding slowly.^[45] This expansion is happening as a consequence of human caused climate change.^[46]^[47] The resulting decrease in oxygen content of the oceans poses a threat to marine life, as well as to people who depend on marine life for nutrition or livelihood.^[48]^[49]^[50] A decrease in ocean oxygen levels affects how productive the ocean is, how nutrients and carbon move around, and how marine habitats function.^[51]^[52]

As the oceans become warmer this increases the loss of oxygen in the oceans. This is because the warmer temperatures increase ocean stratification. The reason for this lies in the multiple connections between density and solubility effects that result from warming.^[53]^[54] As a side effect, the availability of nutrients for marine life is reduced, therefore adding further stress to marine organisms.

Other

A report from NOAA scientists published in the journal Science in May 2008 found that large amounts of relatively acidified water are upwelling to within four miles of the Pacific continental shelf area of North America. This area is a critical zone where most local marine life lives or is born. While the paper dealt only with areas from Vancouver to northern California, other continental shelf areas may be experiencing similar effects.^[55]

Ocean warming can also result in a reduction of the solubility of CO₂ in seawater,^[56] resulting in discharge of CO₂ from the ocean to the atmosphere. In addition to temperature, alkalinity and primary productivity modulate the CO₂ flux between the ocean and the atmosphere.^[57] In basins with very low primary productivity and rapid warming, such as the Eastern Mediterranean sea, a shift from CO₂ sink to source has already been observed.^[58]

A related issue is the methane clathrate reservoirs found under sediments on the ocean floors. These trap large amounts of the greenhouse gas methane, which ocean warming has the potential to release. In 2004 the global inventory of ocean methane clathrates was estimated to occupy between one and five million cubic kilometres.^[59] If all these clathrates were to be spread uniformly across the ocean floor, this would translate to a thickness between three and fourteen metres.^[60] This estimate corresponds to 500–2500 gigatonnes carbon (Gt C), and can be compared with the 5000 Gt C estimated for all other fossil fuel reserves.^[59]^[61]

Effects on marine life

Research indicates that increasing ocean temperatures are taking a toll on the marine ecosystem. A study on phytoplankton changes in the Indian Ocean indicates a decline of up to 20% in marine phytoplankton during the past six decades.^[62] During the summer, the western Indian Ocean is home to one of the largest concentrations of marine phytoplankton blooms in the world when compared to other oceans in the tropics. Increased warming in the Indian Ocean enhances ocean stratification, which prevents nutrient mixing in the euphotic zone where there is ample light available for photosynthesis. Thus, primary production is constrained and the region's entire food web is disrupted. If rapid warming continues, experts predict that the Indian Ocean will transform into an ecological desert and will no longer be productive.^[62] The same study also addresses the abrupt decline of tuna catch rates in the Indian Ocean during the past half century. This decrease is mostly due to increased industrial fisheries, with ocean warming adding further stress to the fish species. These rates show a 50-90% decrease over 5 decades.^[62]

A study that describes climate-driven trends in contemporary ocean productivity looked at global-ocean net primary production (NPP) changes detected from satellite measurements of ocean color from 1997 to 2006.^[63] These measurements can be used to quantify ocean productivity on a global scale and relate changes to environmental factors. They found an initial increase in NPP from 1997 to 1999 followed by a continuous decrease in productivity after 1999. These trends are propelled by the expansive stratified low-latitude oceans and are closely linked to climate variability. This relationship between the physical environment and ocean biology effects the availability of nutrients for phytoplankton growth since these factors influence variations in upper-ocean temperature and stratification.^[63] The downward trends of ocean productivity after 1999 observed in this study can give insight into how climate change can affect marine life in the future.

As stated before, marine life has been decreasing in percentage as the time goes on due to the increase in ocean pollution being the main component plastic that is eaten by marine animals.^[64] Along with marine life, humans are also being affected by ocean pollution. One of the biggest animal protein industries, as it is the seafood industry, is affected since marine life has been decreasing and it is predicted that if they continue using the harmful techniques that are being used, by 2048 there is the possibility of an ocean without fish.^[65] The seafood industry has a big impact in the world's food industry, providing food for approximately 3 billion people.^[66] One of the many famous and trending diets that are out there are the pescatarian diet, in which vegetarian diets followers add fish or other types of seafood in order to obtain the nutrients from the fish.^[67] If it comes to the point in which the seafood industry keep growing, as more people are joining this type of food trends and eating more fish (more demand means more production^[68]), and using techniques that deteriorate the marine life beyond catching the animals we will end up at the point of no return: where the marine life is extinct and we as humans will not be able to consume such as good source of protein in order to meet the required necessities. The ocean pollution does not mean that only marine life is being damaged, but also that we as humans will deprive ourselves from a great privilege as it is seafood and marine life.

Future impacts on marine life

Calculations prepared in or before 2001 from a range of climate models under the SRES A2 emissions scenario, which assumes no action is taken to reduce emissions and regionally divided economic development.

The geographic distribution of surface warming during the 21st century calculated by the HadCM3 climate model if a business as usual scenario is assumed for economic growth and greenhouse gas emissions. In this figure, the globally averaged warming corresponds to 3.0 °C (5.4 °F).

A temperature rise of 1.5 °C above preindustrial levels is projected^{[according to whom?]} to make existence impossible for 10% of fishes in their typical geographical range. A temperature rise of 5 °C above this level is projected to make existence impossible for 60% of fishes in their geographical range. The main reason is Oxygen depletion as one of the consequences of the rise in temperature. Further, the change in temperature and decrease in oxygen is expected to occur too quickly for effective adaptation of affected species. Fishes can migrate to cooler places, but there are not always appropriate spawning sites.^[69]

Increase of water temperature will also have a devastating effect on different oceanic ecosystems like coral reefs. The direct effect is the coral bleaching of these reefs, which live within a narrow temperature margin, so a small increase in temperature would have a drastic effects in these environments. When corals bleach it is because the coral loses 60–90% of their zooxanthellae due to various stressors, ocean temperature being one of them. If the bleaching is prolonged, the coral host would die.^[70]

Although uncertain, another effect of climate change may be the growth, toxicity, and distribution of harmful algal blooms.^[71] These algal blooms have serious effects on not only marine ecosystems, killing sea animals and fish with their toxins, but also for humans as well. Some of these blooms deplete the oxygen around them to levels low enough to kill fish.

Effects on fisheries

Fisheries are affected by climate change in many ways: marine aquatic ecosystems are being affected by rising ocean temperatures,^[72] ocean acidification^[73] and ocean deoxygenation, while freshwater ecosystems are being impacted by changes in water temperature, water flow, and fish habitat loss.^[74] These effects vary in the context of each fishery.^[75] Climate change is modifying fish distributions^[76] and the productivity of marine and freshwater species. Climate change is expected to lead to significant changes in the availability and trade of fish products.^[77] The geopolitical and economic consequences will be significant, especially for the countries most dependent on the sector. The biggest decreases in maximum catch potential can be expected in the tropics, mostly in the South Pacific regions.^[77]^: iv

The impacts of climate change on ocean systems has impacts on the sustainability of fisheries and aquaculture, on the livelihoods of the communities that depend on fisheries, and on the ability of the oceans to capture and store carbon (biological pump). The effect of sea level rise means that coastal fishing communities are significantly impacted by climate change, while changing rainfall patterns and water use impact on inland freshwater fisheries and aquaculture.^[78] Increased risks of floods, diseases, parasites and harmful algal blooms are climate change impacts on aquaculture which can lead to losses of production and infrastructure.^[77]

Effects on marine life and mammals

The effect of climate change on marine life and mammals is a growing concern. Many of the effects of global warming are currently unknown due to unpredictability, but many are becoming increasingly evident today. Some effects are very direct such as loss of habitat, temperature stress, and exposure to severe weather. Other effects are more indirect, such as changes in host pathogen associations, changes in body condition because of predator–prey interaction, changes in exposure to toxins and CO₂ emissions, and increased human interactions.^[79] Despite the large potential impacts of ocean warming on marine mammals, the global vulnerability of marine mammals to global warming is still poorly understood.^[80]

It has been generally assumed that the Arctic marine mammals were the most vulnerable in the face of climate change given the substantial observed and projected decline in Arctic sea ice cover. However, the implementation of a trait-based approach on assessment of the vulnerability of all marine mammals under future global warming has suggested that the North Pacific Ocean, the Greenland Sea and the Barents Sea host the species that are most vulnerable to global warming.^[80] The North Pacific has already been identified as a hotspot for human threats for marine mammals^[81] and now is also a hotspot of vulnerability to global warming. This emphasizes that marine mammals in this region will face double jeopardy from both human activities (e.g., marine traffic, pollution and offshore oil and gas development) and global warming, with potential additive or synergetic effect and as a result, these ecosystems face irreversible consequences for marine ecosystem functioning.^[80]

Species impacted

Polar bears

Polar bears are one of many Arctic marine mammals at risk of population decline due to climate change.^[82] When carbon dioxide is released into the atmosphere, a greenhouse like effect occurs, warming the climate. For polar bears and other Arctic marine mammals, rising temperature is the changing the sea ice formations that they rely on to survive.^[82] In the circumpolar north, the Arctic sea ice is a dynamic ecosystem. The levels of sea ice extent varies by season. While some areas maintain year-round ice, others only have ice on a seasonal basis. The amount of permanent sea ice is decreasing with global temperature increases. Climate change is causing slower formations of sea ice, quicker decline and thinner ice sheets. Polar bears and other Arctic marine mammals are losing their habitat and food sources in result of the sea ice decline.^[83]

Polar bears rely on seals as their main food source.^[84] Although polar bears are strong swimmers, they are not successful at catching seal underwater, therefore polar bears are ambush predators.^[85] When they hunt seals, they wait at seal breathing hole to ambush and haul out their prey onto the sea ice for feeding. With slower sea ice formations, thinner ice sheets and shorter winter seasons, polar bears are having less opportunity for optimal hunting grounds. Polar bears are facing pressures to swim further to gain access to food. This requires more calories spent to obtain calories to sustain their body conditions for reproduction and survival. Researchers use body condition charts to track polar bear population health and reproductive potential.^[86] Trends suggest 12 out of 19 sub populations of polar bears are declining or data deficient.^[87]

Polar bears also rely on sea ice to travel, mate and female polar bears usually choose to den up on the sea ice during denning season.^[88] The sea ice is becoming less stable, forcing pregnant female polar bears to choose less optimal locations for denning.^[83] These aspects are known to result in lower reproduction rates and smaller cub years.

Dolphins

Dolphins are marine mammals with broad geographic extent, making them susceptible to climate change in various ways. The most common effect of climate change on dolphins is the increasing water temperatures across the globe. This has caused a large variety of dolphin species to experience range shifts, in which the species move from their typical geographic region to warmer waters.

In California, the 1982-83 El Niño warming event caused the near-bottom spawning market squid to leave southern California, which caused their predator, the pilot whale, to also leave. As the market squid returned six years later, Risso's dolphins came to feed on the squid. Bottlenose dolphins expanded their range from southern to central California, and stayed even after the warming event subsided.^[89] The Pacific white-sided dolphin has had a decline in population in the southwest Gulf of California, the southern boundary of their distribution. In the 1980s they were abundant with group sizes up to 200 across the entire cool season. Then, in the 2000s, only two groups were recorded with sizes of 20 and 30, and only across the central cool season. This decline was not related to a decline of other marine mammals or prey, so it was concluded to have been caused by climate change as it occurred during a period of warming. Additionally, the Pacific white-sided dolphin had an increase in occurrence on the west coast of Canada from 1984 to 1998.^[90]

In the Mediterranean, sea surface temperatures have increased, as well as salinity, upwelling intensity, and sea levels. Because of this, prey resources have been reduced causing a steep decline in the short-beaked common dolphin Mediterranean subpopulation, which was deemed endangered in 2003. This species now only exists in the Alboran Sea, due to its high productivity, distinct ecosystem, and differing conditions from the rest of the Mediterranean.^[91]

In northwest Europe, many dolphin species have experienced range shifts from the region’s typically colder waters. Warm water dolphins, like the short-beaked common dolphin and striped dolphin, have expanded north of western Britain and into the northern North Sea, even in the winter, which may displace the white-beaked and Atlantic white-sided dolphin that are in that region. The white-beaked dolphin has shown an increase in the southern North Sea since the 1960s because of this. The rough-toothed dolphin and Atlantic spotted dolphin may move to northwest Europe.^[92] In northwest Scotland, white-beaked dolphins (local to the colder waters of the North Atlantic) have decreased while common dolphins (local to warmer waters) have increased from 1992-2003.^[93] Additionally, Fraser’s dolphin, found in tropical waters, was recorded in the UK for the first time in 1996.^[92]

River dolphins are highly affected by climate change as high evaporation rates, increased water temperatures, decreased precipitation, and increased acidification occur.^[89]^[94] River dolphins typically have a higher densities when rivers have a lox index of freshwater degradation and better water quality.^[94] Specifically looking at the Ganges river dolphin, the high evaporation rates and increased flooding on the plains may lead to more human river regulation, decreasing the dolphin population.^[89]

As warmer waters lead to a decrease in dolphin prey, this led to other causes of dolphin population decrease. In the case of bottlenose dolphins, mullet populations decrease due to increasing water temperatures, which leads to a decrease in the dolphins’ health and thus their population.^[89] At the Shark Bay World Heritage Area in Western Australia, the local Indo-Pacific bottlenose dolphin population had a significant decline after a marine heatwave in 2011. This heatwave caused a decrease in prey, which led to a decline in dolphin reproductive rates as female dolphins could not get enough nutrients to sustain a calf.^[95] The resultant decrease in fish population due to warming waters has also influenced humans to see dolphins as fishing competitors or even bait. Humans use dusky dolphins as bait or are killed off because they consume the same fish humans eat and sell for profit.^[89] In the central Brazilian Amazon alone, approximately 600 pink river dolphins are killed each year to be used as bait.^[94] Another side effect of increasing water temperatures is the increase in toxic algae blooms, which has caused a mass die-off of bottlenose dolphins.^[92]

Potential effects

Marine mammals have evolved to live in oceans, but climate change is affecting their natural habitat.^[96]^[97]^[98]^[99] Some species may not adapt fast enough, which might lead to their extinction.^[100]

Ocean warming

During the last century, the global average land and sea surface temperature has increased due to an increased greenhouse effect from human activities.^[101] From 1960 to through 2019, the average temperature for the upper 2000 meters of the oceans has increased by 0.12 degree Celsius, whereas the ocean surface has warmed up to 1.2 degree Celsius from the pre-industrial era.^[102]

Marine organisms usually tend to encounter relatively stable temperatures compared with terrestrial species and thus are likely to be more sensitive to temperature change than terrestrial organisms.^[103] Therefore, the ocean warming will lead to increased species migration, as endangered species look for a more suitable habitat. If sea temperatures continue to rise, then some fauna may move to cooler water and some range-edge species may disappear from regional waters or experienced a reduced global range.^[103] Change in the abundance of some species will alter the food resources available to marine mammals, which then results in marine mammals’ biogeographic shifts. Additionally, if a species cannot successfully migrate to a suitable environment, unless it learns to adapt to rising ocean temperatures, it will face extinction.

Sea level rise is also important when assessing the impacts of global warming on marine mammals, since it affects coastal environments that marine mammals species rely.^[104]

Primary productivity

Changes in temperatures will impact the location of areas with high primary productivity. Primary producers, such as plankton,^[105]^[106]^[107]^[108] are the main food source for marine mammals such as some whales. Species migration will therefore be directly affected by locations of high primary productivity. Water temperature changes also affect ocean turbulence, which has a major impact on the dispersion of plankton and other primary producers.^[109] Due to global warming and increased glacier melt, thermohaline circulation patterns may be altered by increasing amounts of freshwater released into oceans and, therefore, changing ocean salinity. Thermohaline circulation is responsible for bringing up cold, nutrient-rich water from the depths of the ocean, a process known as upwelling.^[110]

Ocean acidification

About a quarter of the emitted CO_2, about 26 million tons is absorbed by the ocean every day.^[111] Consequently, the dissolution of anthropogenic carbon dioxide (CO₂) in seawater causes a decrease in pH which is corresponding to an increase in acidity of the oceans with consequences for marine biota. Since the beginning of the industrial revolution, ocean acidity has increased by 30% (the pH decreased from 8.2 to 8.1).^[111] It is projected that the ocean will experience severe acidification under RCP 8.5, high CO₂ emission scenario, and less intense acidification under RCP 2.6, low CO₂ emission scenario. Ocean acidification will impact marine organisms (corals, mussels, oysters) in producing their limestone skeleton or shell. When CO₂ dissolves in seawater, it increases protons (H+ ions) but reduces certain molecules, such as carbonate ions in which many oysters needed to produce their limestone skeleton or shell.^[111] The shell and the skeleton of these species may become less dense or strong. This also may make coral reefs become more vulnerable to storm damage, and slow down its recovery. In addition, marine organisms may experience changes in growth, development, abundance, and survival in response to ocean acidification.

Sea ice changes

Sea ice, a defining characteristic of polar marine environment, is changing rapidly which has impacts on marine mammals. Climate change models predict changes to the sea ice leading to loss of the sea ice habitat, elevations of water and air temperature, and increased occurrence of severe weather. The loss of sea ice habitat will reduced the abundance of seal prey for marine mammals, particularly polar bears. Initially, polar bears may be favored by an increase in leads in the ice that make more suitable seal habitat available but, as the ice thins further, they will have to travel more, using energy to keep in contact with favored habitat.^[112] There also may be some indirect effect of sea ice changes on animal heath due to alterations in pathogen transmission, effect on animals on body condition caused by shift in the prey based/food web, changes in toxicant exposure associated with increased human habitation in the Arctic habitat.^[113]

Hypoxia

Hypoxia occurs in the variety of coastal environment when the dissolved of oxygen (DO) is depleted to a certain low level, where aquatic organisms, especially benthic fauna, become stressed or die due to the lack of oxygen.^[114] Hypoxia occurs when the coastal region enhance Phosphorus release from sediment and increase Nitrate (N) loss. This chemical scenario supports favorable growth for cyanobacteria which contribute to the hypoxia and ultimately sustain eutrophication.^[115] Hypoxia degrades an ecosystem by damaging the bottom fauna habitats, altering the food web, changing the nitrogen and phosphate cycling, decreasing fishery catch, and enhancing the water acidification.^[115] There were 500 areas in the world with reported coastal hypoxia in 2011, with Baltic Sea contains the largest hypoxia zone in the world.^[116] These numbers are expected to increase due to the worsening condition of coastal areas caused by the excessive anthropogenic nutrient loads that stimulate intensified eutrophication. The rapidly changing climate in particularly, global warming, also contributes to the increase of Hypoxia occurrence that damaging marine mammals and marine/coastal ecosystem.

Notes

^ Cheng, Lijing; Abraham, John; Hausfather, Zeke; Trenberth, Kevin E. (2019). "How fast are the oceans warming?". Science. 363 (6423): 128–129. Bibcode:2019Sci...363..128C. doi:10.1126/science.aav7619. ISSN 0036-8075. PMID 30630919. S2CID 57825894.
^ Humphreys, M. P. (2016). "Climate sensitivity and the rate of ocean acidification: future impacts, and implications for experimental design". ICES Journal of Marine Science. 74 (4): 934–940. doi:10.1093/icesjms/fsw189.
^ "The Oceans Are Heating Up Faster Than Expected". scientific american. Retrieved 3 March 2020.
^ "Global Annual Mean Surface Air Temperature Change". NASA. Retrieved 23 February 2020.
^ IPCC AR5 SYR Glossary 2014, p. 124.
^ ^a ^b Bindoff, N.L.; Willebrand, J.; Artale, V.; Cazenave, A.; Gregory, J.; Gulev, S.; Hanawa, K.; Le Quéré, C.; Levitus, S.; Nojiri, Y.; Shum, C.K.; Talley, L.D.; Unnikrishnan, A. (2007). Solomon, S.; D. Qin; M. Manning; Z. Chen; M. Marquis; K.B. Averyt; M. Tignor; H.L. Miller (eds.). "Observations: Oceanic Climate Change and Sea Level. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change" (PDF). Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Archived from the original (PDF) on 2017-05-13. Retrieved 2007-12-29.
^ Gille, Sarah T. (2002-02-15). "Warming of the Southern Ocean Since the 1950s". Science. 295 (5558): 1275–1277. Bibcode:2002Sci...295.1275G. doi:10.1126/science.1065863. PMID 11847337. S2CID 31434936.
^ ^a ^b "NOAA: NESDIS: NCDC: Frequently Asked Questions: How do we know the Earth's climate is warming?". NOAA. 2010-03-10.
^ Bindoff, N. L.; Cheung, W. W. L.; Kairo, J. G.; Arístegui, J.; et al. (2019). "Chapter 5: Changing Ocean, Marine Ecosystems, and Dependent Communities" (PDF). IPCC SROCC 2019. p. 457. Archived (PDF) from the original on 28 May 2020. Retrieved 24 May 2020.
^ Bindoff, N. L.; Cheung, W. W. L.; Kairo, J. G.; Arístegui, J.; et al. (2019). "Chapter 5: Changing Ocean, Marine Ecosystems, and Dependent Communities" (PDF). IPCC SROCC 2019. p. 457.^{[permanent dead link]}
^ Bindoff, N. L.; Cheung, W. W. L.; Kairo, J. G.; Arístegui, J.; et al. (2019). "Chapter 5: Changing Ocean, Marine Ecosystems, and Dependent Communities" (PDF). IPCC SROCC 2019. p. 463. Archived (PDF) from the original on 20 December 2019. Retrieved 28 December 2019.
^ IPCC, 2019: Summary for Policymakers. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D. C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N. M. Weyer (eds.)]. Cambridge University Press, Cambridge, UK and New York, New York, US. https://doi.org/10.1017/9781009157964.001.
^ "WMO annual report highlights continuous advance of climate change". World Meteorological Organization. 21 April 2023. Press Release Number: 21042023
^ ^a ^b ^c IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J. B. R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, New York, US, pp. 3−32, doi:10.1017/9781009157896.001.
^ WCRP Global Sea Level Budget Group (2018). "Global sea-level budget 1993–present". Earth System Science Data. 10 (3): 1551–1590. Bibcode:2018ESSD...10.1551W. doi:10.5194/essd-10-1551-2018. This corresponds to a mean sea-level rise of about 7.5 cm over the whole altimetry period. More importantly, the GMSL curve shows a net acceleration, estimated to be at 0.08mm/yr².
^ National Academies of Sciences, Engineering, and Medicine (2011). "Synopsis". Climate Stabilization Targets: Emissions, Concentrations, and Impacts over Decades to Millennia. Washington, DC: The National Academies Press. p. 5. doi:10.17226/12877. ISBN 978-0-309-15176-4. Box SYN-1: Sustained warming could lead to severe impacts
^ Fox-Kemper, B.; Hewitt, Helene T.; Xiao, C.; Aðalgeirsdóttir, G.; Drijfhout, S. S.; Edwards, T. L.; Golledge, N. R.; Hemer, M.; Kopp, R. E.; Krinner, G.; Mix, A. (2021). Masson-Delmotte, V.; Zhai, P.; Pirani, A.; Connors, S. L.; Péan, C.; Berger, S.; Caud, N.; Chen, Y.; Goldfarb, L. (eds.). "Chapter 9: Ocean, Cryosphere and Sea Level Change" (PDF). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, NY, US.
^ (Trujillo & Thurman 2008, p. 172)
^ (Trujillo & Thurman 2008, p. 207)
^ Talley, L. (2000). Sio 210 talley topic 5: North Atlantic circulation and water masses. thermohaline forcing.
^ Roach, J. (2005, June 27). Global warming may alter atlantic currents, study says.
^ ^a ^b Lenton, T. M.; Held, H.; Kriegler, E.; Hall, J. W.; Lucht, W.; Rahmstorf, S.; Schellnhuber, H. J. (2008). "Inaugural Article: Tipping elements in the Earth's climate system". Proceedings of the National Academy of Sciences. 105 (6): 1786–1793. Bibcode:2008PNAS..105.1786L. doi:10.1073/pnas.0705414105. PMC 2538841. PMID 18258748.
^ IPCC (2007). M.L. Parry; et al. (eds.). Summary for Policymakers. In: Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (PDF). Cambridge, U.K., and New York, N.Y., U.S.A.: Cambridge University Press. pp. 7–22. Archived from the original (PDF) on 2018-01-13. Retrieved 2007-11-30.
^ Carrington, Damian (5 August 2021). "Climate crisis: Scientists spot warning signs of Gulf Stream collapse". Guardian. Retrieved 6 August 2021.
^ (Trujillo & Thurman 2008, p. 216)
^ Canadell, J. G. et al (2007, November 01). Is the ocean carbon sink sinking?
^ Webster, P. J. et al. (2005). Changes in tropical cyclone number, duration, and intensity in a warming environment.
^ (Trujillo & Thurman 2008, p. 194)
^ (Trujillo & Thurman 2008, p. 195)
^ Renner, Jeff (1993). Northwest marine weather. the Mountaineers. pp. 71–72.
^ Collier, Michael (2002). Floods, Droughts, and Climate Change. The University of Arizona Press. pp. 13–19.
^ Archer, David (2009). The Long Thaw. Princeton University Press. pp. 69–77.
^ Weller, Evan; Min, Seung-Ki; Cai, Wenju; Zwiers, Francis W.; Kim, Yeon-Hee; Lee, Donghyun (July 2016). "Human-caused Indo-Pacific warm pool expansion". Science Advances. 2 (7): e1501719. Bibcode:2016SciA....2E1719W. doi:10.1126/sciadv.1501719. ISSN 2375-2548. PMC 4942332. PMID 27419228.
^ Roxy, M. K.; Dasgupta, Panini; McPhaden, Michael J.; Suematsu, Tamaki; Zhang, Chidong; Kim, Daehyun (November 2019). "Twofold expansion of the Indo-Pacific warm pool warps the MJO life cycle". Nature. 575 (7784): 647–651. Bibcode:2019Natur.575..647R. doi:10.1038/s41586-019-1764-4. ISSN 0028-0836. OSTI 1659516. PMID 31776488. S2CID 208329374.
^ ^a ^b Tripati, Aradhna, Lab 5-Ocean pH, Ocean pH Reading, E&SSCI15-1, UCLA, 2012
^ University Of Wyoming (2004, January 13). 2004/01/040113080810.htm Ocean Floor Reveals Clues To Global Warming. ScienceDaily. Retrieved May 21, 2012
^ Pohlman, John W.; Greinert, Jens; Ruppel, Carolyn; Silyakova, Anna; Vielstadte, Lisa; Casso, Michael; Mienert, Jurgen; Bunz, Stefan (May 8, 2017). "Enhanced CO2 uptake at a shallow Arctic Ocean seep field overwhelms the positive warming potential of emitted methane". PNAS. 114 (21): 5355–5360. Bibcode:2017PNAS..114R5355P. doi:10.1073/pnas.1618926114. PMC 5448205. PMID 28484018.
^ Terhaar, Jens; Frölicher, Thomas L.; Joos, Fortunat (2023). "Ocean acidification in emission-driven temperature stabilization scenarios: the role of TCRE and non-CO₂ greenhouse gases". Environmental Research Letters. 18 (2): 024033. Bibcode:2023ERL....18b4033T. doi:10.1088/1748-9326/acaf91. ISSN 1748-9326. S2CID 255431338. Figure 1f
^ Ocean acidification due to increasing atmospheric carbon dioxide (PDF). Royal Society. 2005. ISBN 0-85403-617-2.
^ Jiang, Li-Qing; Carter, Brendan R.; Feely, Richard A.; Lauvset, Siv K.; Olsen, Are (2019). "Surface ocean pH and buffer capacity: past, present and future". Scientific Reports. 9 (1): 18624. Bibcode:2019NatSR...918624J. doi:10.1038/s41598-019-55039-4. PMC 6901524. PMID 31819102. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License Archived 16 October 2017 at the Wayback Machine
^ Zhang, Y.; Yamamoto-Kawai, M.; Williams, W.J. (2020-02-16). "Two Decades of Ocean Acidification in the Surface Waters of the Beaufort Gyre, Arctic Ocean: Effects of Sea Ice Melt and Retreat From 1997–2016". Geophysical Research Letters. 47 (3). doi:10.1029/2019GL086421. S2CID 214271838.
^ Beaupré-Laperrière, Alexis; Mucci, Alfonso; Thomas, Helmuth (2020-07-31). "The recent state and variability of the carbonate system of the Canadian Arctic Archipelago and adjacent basins in the context of ocean acidification". Biogeosciences. 17 (14): 3923–3942. Bibcode:2020BGeo...17.3923B. doi:10.5194/bg-17-3923-2020. S2CID 221369828.
^ ^a ^b Laffoley, D; Baxter, JM (2019). Ocean deoxygenation: everyone's problem. Switzerland: Gland. p. 562. ISBN 978-2-8317-2013-5.
^ Limburg, Karin E.; Breitburg, Denise; Swaney, Dennis P.; Jacinto, Gil (2020-01-24). "Ocean Deoxygenation: A Primer". One Earth. 2 (1): 24–29. Bibcode:2020OEart...2...24L. doi:10.1016/j.oneear.2020.01.001. ISSN 2590-3330. S2CID 214348057.
^ Oschlies, Andreas; Brandt, Peter; Stramma, Lothar; Schmidtko, Sunke (2018). "Drivers and mechanisms of ocean deoxygenation". Nature Geoscience. 11 (7): 467–473. Bibcode:2018NatGe..11..467O. doi:10.1038/s41561-018-0152-2. ISSN 1752-0894. S2CID 135112478.
^ Stramma, L; Johnson, GC; Printall, J; Mohrholz, V (2008). "Expanding Oxygen-Minimum Zones in the Tropical Oceans". Science. 320 (5876): 655–658. Bibcode:2008Sci...320..655S. doi:10.1126/science.1153847. PMID 18451300. S2CID 206510856.
^ Mora, C; et al. (2013). "Biotic and Human Vulnerability to Projected Changes in Ocean Biogeochemistry over the 21st Century". PLOS Biology. 11 (10): e1001682. doi:10.1371/journal.pbio.1001682. PMC 3797030. PMID 24143135.
^ Carrington (2018-01-04). "Environment. Oceans suffocating as huge dead zones quadruple since 1950, scientists warn". The Guardian. ISSN 0261-3077. Retrieved 2023-07-04.
^ Long, Matthew C.; Deutsch, Curtis; Ito, Taka (2016). "Finding forced trends in oceanic oxygen". Global Biogeochemical Cycles. 30 (2): 381–397. Bibcode:2016GBioC..30..381L. doi:10.1002/2015GB005310. ISSN 0886-6236. S2CID 130885459.
^ Pearce, Rosamund (2018-06-15). "Guest post: How global warming is causing ocean oxygen levels to fall". Carbon Brief. Retrieved 2023-07-04.
^ Harvey, Fiona (2019-12-07). "Oceans losing oxygen at unprecedented rate, experts warn". The Guardian. ISSN 0261-3077. Retrieved 2019-12-07.
^ Laffoley, D. & Baxter, J.M. (eds.) (2019). Ocean deoxygenation: Everyone's problem - Causes, impacts, consequences and solutions. IUCN, Switzerland.
^ Bednaršek, N., Harvey, C.J., Kaplan, I.C., Feely, R.A. and Možina, J. (2016) "Pteropods on the edge: Cumulative effects of ocean acidification, warming, and deoxygenation". Progress in Oceanography, 145: 1–24. doi:10.1016/j.pocean.2016.04.002
^ Keeling, Ralph F., and Hernan E. Garcia (2002) "The change in oceanic O2 inventory associated with recent global warming." Proceedings of the National Academy of Sciences, 99(12): 7848–7853. doi:10.1073/pnas.122154899
^ Feely, R. A.; Sabine, C. L.; Hernandez-Ayon, J. M.; Ianson, D.; Hales, B. (2008). "Evidence for Upwelling of Corrosive "Acidified" Water onto the Continental Shelf". Science. 320 (5882): 1490–2. Bibcode:2008Sci...320.1490F. CiteSeerX 10.1.1.328.3181. doi:10.1126/science.1155676. PMID 18497259. S2CID 35487689.
^ Zeebe, Richard E.; Wolf-Gladrow, D. (2001). CO2 in seawater : equilibrium, kinetics, isotopes. Amsterdam. p. 346. ISBN 9780444509468.{{cite book}}: CS1 maint: location missing publisher (link)
^ Dai, Minhan; Cao, Zhimian; Guo, Xianghui; Zhai, Weidong; Liu, Zhiyu; Yin, Zhiqiang; Xu, Yanping; Gan, Jianping; Hu, Jianyu; Du, Chuanjun (28 May 2013). "Why are some marginal seas sources of atmospheric CO2 ?: SOME MARGINAL SEAS ARE CO2 SOURCES". Geophysical Research Letters. 40 (10): 2154–2158. doi:10.1002/grl.50390.
^ Sisma-Ventura, Guy; Bialik, Or M.; Yam, Ruth; Herut, Barak; Silverman, Jacob (November 2017). "p CO 2 variability in the surface waters of the ultra-oligotrophic Levantine Sea: Exploring the air–sea CO 2 fluxes in a fast warming region". Marine Chemistry. 196: 13–23. doi:10.1016/j.marchem.2017.06.006.
^ ^a ^b Milkov, A. V. (2004). "Global estimates of hydrate-bound gas in marine sediments: How much is really out there?". Earth-Science Reviews. 66 (3–4): 183–197. Bibcode:2004ESRv...66..183M. doi:10.1016/j.earscirev.2003.11.002.
^ The oceans occupy 361 million sq km
^ USGS World Energy Assessment Team, 2000. US Geological Survey world petroleum assessment 2000––description and results. USGS Digital Data Series DDS-60
^ ^a ^b ^c Roxy, M.K. (2016). "A reduction in marine primary productivity driven by rapid warming over the tropical Indian Ocean" (PDF). Geophysical Research Letters. 43 (2): 826–833. Bibcode:2016GeoRL..43..826R. doi:10.1002/2015GL066979.
^ ^a ^b Behrenfeld, Michael J.; O'Malley, Robert T.; Siegel, David A.; McClain, Charles R.; Sarmiento, Jorge L.; Feldman, Gene C.; Milligan, Allen J.; Falkowski, Paul G.; Letelier, Ricardo M.; Boss, Emmanuel S. (December 2006). "Climate-driven trends in contemporary ocean productivity". Nature. 444 (7120): 752–755. Bibcode:2006Natur.444..752B. doi:10.1038/nature05317. PMID 17151666. S2CID 4414391.
^ "Marine pollution, explained". National Geographic. 2019-08-02. Retrieved 2020-04-07.
^ Humphreys, M. P. (2016). "Climate sensitivity and the rate of ocean acidification: future impacts, and implications for experimental design". ICES Journal of Marine Science. 74 (4): 934–940. doi:10.1093/icesjms/fsw189.
^ "Sustainable Seafood | Industries | WWF". World Wildlife Fund. Retrieved 2020-04-07.
^ "What is a pescatarian diet?". BBC Good Food. Retrieved 2020-04-07.
^ Chappelow, Jim. "Learn about Law of Supply and Demand". Investopedia. Retrieved 2020-04-07.
^ Vaughan, Adam (2 July 2020). "Climate change will make world too hot for 60 per cent of fish species". New Scientist. Retrieved 3 July 2020.
^ Buchheim, Jason "Coral Reef Bleaching," Odyssey Expeditions Tropical Marine Biology Voyages
^ "Harmful Algal Blooms: Simple Plants with Toxic Implications," National Oceanic and Atmospheric Administration.
^ Observations: Oceanic Climate Change and Sea Level Archived 2017-05-13 at the Wayback Machine In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. (15 MB).
^ Doney, S. C. (March 2006). "The Dangers of Ocean Acidification" (PDF). Scientific American. 294 (3): 58–65. Bibcode:2006SciAm.294c..58D. doi:10.1038/scientificamerican0306-58. PMID 16502612.
^ US EPA, OAR (2015-04-07). "Climate Action Benefits: Freshwater Fish". US EPA. Retrieved 2020-04-06.
^ Weatherdon, Lauren V.; Magnan, Alexandre K.; Rogers, Alex D.; Sumaila, U. Rashid; Cheung, William W. L. (2016). "Observed and Projected Impacts of Climate Change on Marine Fisheries, Aquaculture, Coastal Tourism, and Human Health: An Update". Frontiers in Marine Science. 3. doi:10.3389/fmars.2016.00048. ISSN 2296-7745.
^ Cheung, W.W.L.; et al. (October 2009). Redistribution of Fish Catch by Climate Change. A Summary of a New Scientific Analysis (PDF). Sea Around Us (Report). Archived from the original (PDF) on 2011-07-26.
^ ^a ^b ^c Manuel Barange; Tarûb Bahri; Malcolm C. M. Beveridge; K. L. Cochrane; S. Funge Smith; Florence Poulain, eds. (2018). Impacts of climate change on fisheries and aquaculture: synthesis of current knowledge, adaptation and mitigation options. Rome: Food and Agriculture Organization of the United Nations. ISBN 978-92-5-130607-9. OCLC 1078885208.
^ Intergovernmental Panel on Climate Change (IPCC), ed. (2022), "Sea Level Rise and Implications for Low-Lying Islands, Coasts and Communities", The Ocean and Cryosphere in a Changing Climate: Special Report of the Intergovernmental Panel on Climate Change, Cambridge: Cambridge University Press, pp. 321–446, doi:10.1017/9781009157964.006, ISBN 978-1-00-915796-4, S2CID 246522316, retrieved 2022-04-06
^ Burek, Kathy A.; Gulland, Frances M. D.; O'Hara, Todd M. (2008). "Effects of Climate Change on Arctic Marine Mammal Health" (PDF). Ecological Applications. 18 (2): S126–S134. doi:10.1890/06-0553.1. ISSN 1051-0761. JSTOR 40062160. PMID 18494366.
^ ^a ^b ^c Albouy, Camille; Delattre, Valentine; Donati, Giulia; Frölicher, Thomas L.; Albouy-Boyer, Severine; Rufino, Marta; Pellissier, Loïc; Mouillot, David; Leprieur, Fabien (December 2020). "Global vulnerability of marine mammals to global warming". Scientific Reports. 10 (1): 548. Bibcode:2020NatSR..10..548A. doi:10.1038/s41598-019-57280-3. ISSN 2045-2322. PMC 6969058. PMID 31953496.
^ Avila, Isabel C.; Kaschner, Kristin; Dormann, Carsten F. (May 2018). "Current global risks to marine mammals: Taking stock of the threats". Biological Conservation. 221: 44–58. doi:10.1016/j.biocon.2018.02.021. ISSN 0006-3207.
^ ^a ^b Stirling, Ian; Lunn, Nicholas J.; Iacozza, John (1999-01-01). "Long-term Trends in the Population Ecology of Polar Bears in Western Hudson Bay in Relation to Climatic Change". Arctic. 52 (3). doi:10.14430/arctic935. ISSN 1923-1245.
^ ^a ^b T., DeWeaver, Eric (2013). Arctic Sea Ice Decline : Observations, Projections, Mechanisms, and Implications. Wiley. ISBN 978-1-118-67158-0. OCLC 850080201.{{cite book}}: CS1 maint: multiple names: authors list (link)
^ Malcolm., Penny (2000). Polar bear : habitats, life cycles, food chains, threats. Raintree Steck-Vaughn Publishers. ISBN 0-7398-1060-X. OCLC 41565047.
^ D.), Tarbox, A. D. (Angelique (2009). An Arctic tundra food chain. Creative Education. ISBN 978-1-58341-596-2. OCLC 78072263.{{cite book}}: CS1 maint: multiple names: authors list (link)
^ Michael., Pagano, Anthony (2018). Polar Bear (Ursus maritimus) Behavior and Energetics : New Metrics for Examining the Physiological Impact of a Changing Arctic Environment. ISBN 978-0-438-24947-9. OCLC 1076545435.{{cite book}}: CS1 maint: multiple names: authors list (link)
^ V., Regehr, Eric (2006). Polar bear population status in the southern Beaufort Sea. U.S. Geological Survey. OCLC 76881605.{{cite book}}: CS1 maint: multiple names: authors list (link)
^ Riddihough, G. (2010-03-18). "Polar Bear, Polar Bear". Science. 327 (5972): 1430–1431. Bibcode:2010Sci...327.1430R. doi:10.1126/science.327.5972.1430-d. ISSN 0036-8075.
^ ^a ^b ^c ^d ^e Würsig, Bernd; Reeves, Randall R.; Ortega-Ortiz, J. G. (2001), Evans, Peter G. H.; Raga, Juan Antonio (eds.), "Global Climate Change and Marine Mammals", Marine Mammals: Biology and Conservation, Boston, MA: Springer US, pp. 589–608, doi:10.1007/978-1-4615-0529-7_17, ISBN 978-1-4615-0529-7, retrieved 2021-05-01
^ Salvadeo, CJ; Lluch-Belda, D; Gómez-Gallardo, A; Urbán-Ramírez, J; MacLeod, CD (2010-03-10). "Climate change and a poleward shift in the distribution of the Pacific white-sided dolphin in the northeastern Pacific". Endangered Species Research. 11 (1): 13–19. doi:10.3354/esr00252. ISSN 1863-5407.
^ Cañadas, A.; Vázquez, J.A. (2017-07-01). "Common dolphins in the Alboran Sea: Facing a reduction in their suitable habitat due to an increase in Sea surface temperature". Deep Sea Research Part II: Topical Studies in Oceanography. 141: 306–318. Bibcode:2017DSRII.141..306C. doi:10.1016/j.dsr2.2017.03.006. ISSN 0967-0645.
^ ^a ^b ^c Evans, Peter G.H.; Bjørge, Arne (November 28, 2013). "Impacts of climate change on marine mammals" (PDF). MCCIP Science Review 2013.
^ MacLeod, Colin D.; Bannon, Sarah M.; Pierce, Graham J.; Schweder, Caroline; Learmonth, Jennifer A.; Herman, Jerry S.; Reid, Robert J. (2005-08-01). "Climate change and the cetacean community of north-west Scotland". Biological Conservation. 124 (4): 477–483. doi:10.1016/j.biocon.2005.02.004. ISSN 0006-3207.
^ ^a ^b ^c Gomez-Salazar, Catalina; Coll, Marta; Whitehead, Hal (2012-12-01). "River dolphins as indicators of ecosystem degradation in large tropical rivers". Ecological Indicators. 23: 19–26. doi:10.1016/j.ecolind.2012.02.034. ISSN 1470-160X.
^ Wild, Sonja; Krützen, Michael; Rankin, Robert W.; Hoppitt, William J.E.; Gerber, Livia; Allen, Simon J. (2019-04-01). "Long-term decline in survival and reproduction of dolphins following a marine heatwave". Current Biology. 29 (7): R239–R240. doi:10.1016/j.cub.2019.02.047. ISSN 0960-9822. PMID 30939303.
^ Harwood, John (1 August 2001). "Marine mammals and their environment in the twenty-first century". Journal of Mammalogy. 82 (3): 630–640. doi:10.1644/1545-1542(2001)082<0630:MMATEI>2.0.CO;2. ISSN 0022-2372.
^ Simmonds, Mark P.; Isaac, Stephen J. (5 March 2007). "The impacts of climate change on marine mammals: early signs of significant problems". Oryx. 41 (1): 19–26. doi:10.1017/s0030605307001524.
^ Tynan, Cynthia T.; DeMaster, Douglas P. (1997). "Observations and Predictions of Arctic Climatic Change: Potential Effects on Marine Mammals" (PDF). Arctic. 50 (4): 308–322. doi:10.14430/arctic1113. Animals have a high risk of mortality.
^ Learmonth, JA; Macleod, CD; Santos, MB; Pierce, GJ; Crick, HQP; Robinson, RA (2006). "Potential effects of climate change on marine mammals". In Gibson, RN; Atkinson, RJA; Gordon, JDM (eds.). Oceanography and marine biology an annual review. Volume 44. Boca Raton: Taylor & Francis. pp. 431–464. ISBN 9781420006391.
^ Laidre, Kristin L.; Stirling, Ian; Lowry, Lloyd F.; Wiig, Øystein; Heide-Jørgensen, Mads Peter; Ferguson, Steven H. (January 1, 2008). "Quantifying the Sensitivity of Arctic Marine Mammals to Climate-Induced Habitat Change". Ecological Applications. 18 (2): S97–S125. doi:10.1890/06-0546.1. JSTOR 40062159. PMID 18494365.
^ Map Shows Vast Regions of Ocean Are Warmer March 30, 2013 Scientific American
^ Cheng, Lijing; Abraham, John; Zhu, Jiang; Trenberth, Kevin E.; Fasullo, John; Boyer, Tim; Locarnini, Ricardo; Zhang, Bin; Yu, Fujiang; Wan, Liying; Chen, Xingrong (February 2020). "Record-Setting Ocean Warmth Continued in 2019". Advances in Atmospheric Sciences. 37 (2): 137–142. Bibcode:2020AdAtS..37..137C. doi:10.1007/s00376-020-9283-7. ISSN 0256-1530. S2CID 210157933.
^ ^a ^b Yao, Cui-Luan; Somero, George N. (February 2014). "The impact of ocean warming on marine organisms". Chinese Science Bulletin. 59 (5–6): 468–479. Bibcode:2014ChSBu..59..468Y. doi:10.1007/s11434-014-0113-0. ISSN 1001-6538. S2CID 98449170.
^ Glick, Patrick; Clough, Jonathan; Nunley, Brad. "Sea-Level Rise and Coastal Habitats in the Chesapeake Bay Region" (PDF). National Wildlife Federation. Retrieved November 8, 2014.
^ Sarmento, H.; Montoya, JM.; Vázquez-Domínguez, E.; Vaqué, D.; Gasol, JM. (2010). "Warming effects on marine microbial food web processes: how far can we go when it comes to predictions?". Philosophical Transactions of the Royal Society B: Biological Sciences. 365 (1549): 2137–2149. doi:10.1098/rstb.2010.0045. PMC 2880134. PMID 20513721.
^ Vázquez-Domínguez, E.; Vaqué, D.; Gasol, JM. (2007). "Ocean warming enhances respiration and carbon demand of coastal microbial plankton". Global Change Biology. 13 (7): 1327–1334. Bibcode:2007GCBio..13.1327V. doi:10.1111/j.1365-2486.2007.01377.x. hdl:10261/15731.
^ Vázquez-Domínguez, E.; Vaqué, D.; Gasol, JM. (2012). "Temperature effects on the heterotrophic bacteria, heterotrophic nanoflagellates, and microbial top predators of NW Mediterranean". Aquatic Microbial Ecology. 67 (2): 107–121. doi:10.3354/ame01583.
^ Mazuecos, E.; Arístegui, J.; Vázquez-Domínguez, E.; Ortega-Retuerta, E.; Gasol, JM.; Reche, I. (2012). "Temperature control of microbial respiration and growth efficiency in the mesopelagic zone of the South Atlantic and Indian Oceans". Deep Sea Research Part I: Oceanographic Research Papers. 95 (2): 131–138. doi:10.3354/ame01583.
^ Castilla, Juan Carlos. "Marine Ecosystems, Human Impacts on". Encyclopedia of Biodiversity (2 ed.). Academic Press. pp. 56–63.
^ Haldar, Ishita (30 April 2018). Global Warming: The Causes and Consequences. Readworthy. ISBN 9788193534571.
^ ^a ^b ^c Euzen, Agathe (2017). The ocean revealed. Paris: CNRS ÉDITIONS. ISBN 978-2-271-11907-0.
^ Derocher, A. E. (2004-04-01). "Polar Bears in a Warming Climate". Integrative and Comparative Biology. 44 (2): 163–176. doi:10.1093/icb/44.2.163. ISSN 1540-7063. PMID 21680496. S2CID 13716867.
^ Burek, Kathy A.; Gulland, Frances M. D.; O'Hara, Todd M. (March 2008). "Effects of Climate Change on Arctic Marine Mammal Health". Ecological Applications. 18 (sp2): S126–S134. doi:10.1890/06-0553.1. ISSN 1051-0761. PMID 18494366.
^ Ekau, W.; Auel, H.; Pörtner, H.-O.; Gilbert, D. (2010-05-21). "Impacts of hypoxia on the structure and processes in pelagic communities (zooplankton, macro-invertebrates and fish)". Biogeosciences. 7 (5): 1669–1699. Bibcode:2010BGeo....7.1669E. doi:10.5194/bg-7-1669-2010. ISSN 1726-4189.
^ ^a ^b Conley, Daniel J.; Björck, Svante; Bonsdorff, Erik; Carstensen, Jacob; Destouni, Georgia; Gustafsson, Bo G.; Hietanen, Susanna; Kortekaas, Marloes; Kuosa, Harri; Markus Meier, H. E.; Müller-Karulis, Baerbel (2009-05-15). "Hypoxia-Related Processes in the Baltic Sea". Environmental Science & Technology. 43 (10): 3412–3420. Bibcode:2009EnST...43.3412C. doi:10.1021/es802762a. ISSN 0013-936X. PMID 19544833.
^ Conley*, Daniel J.; Bonsdorff, Erik; Carstensen, Jacob; Destouni, Georgia; Gustafsson, Bo G.; Hansson, Lars-Anders; Rabalais, Nancy N.; Voss, Maren; Zillén, Lovisa (2009-05-15). "Tackling Hypoxia in the Baltic Sea: Is Engineering a Solution?". Environmental Science & Technology. 43 (10): 3407–3411. Bibcode:2009EnST...43.3407C. doi:10.1021/es8027633. ISSN 0013-936X. PMID 19544832.

References

External links

DISCOVER – satellite-based ocean and climate data since 1979 from NASA
Marine Mammal Commission
United Nations Environment Programme World Conservation Monitoring Centre

[1] Cheng, Lijing; Abraham, John; Hausfather, Zeke; Trenberth, Kevin E. (2019). "How fast are the oceans warming?". Science. 363 (6423): 128–129. Bibcode:2019Sci...363..128C. doi:10.1126/science.aav7619. ISSN 0036-8075. PMID 30630919. S2CID 57825894.

[:03-2] Humphreys, M. P. (2016). "Climate sensitivity and the rate of ocean acidification: future impacts, and implications for experimental design". ICES Journal of Marine Science. 74 (4): 934–940. doi:10.1093/icesjms/fsw189.

[ocean_heat_92-3] "The Oceans Are Heating Up Faster Than Expected". scientific american. Retrieved 3 March 2020.

[nasa_temperatures-4] "Global Annual Mean Surface Air Temperature Change". NASA. Retrieved 23 February 2020.

[ipcc_pre_industrial_baseline-5] IPCC AR5 SYR Glossary 2014, p. 124.

[IPCC_4th_assessment_f-6] Bindoff, N.L.; Willebrand, J.; Artale, V.; Cazenave, A.; Gregory, J.; Gulev, S.; Hanawa, K.; Le Quéré, C.; Levitus, S.; Nojiri, Y.; Shum, C.K.; Talley, L.D.; Unnikrishnan, A. (2007). Solomon, S.; D. Qin; M. Manning; Z. Chen; M. Marquis; K.B. Averyt; M. Tignor; H.L. Miller (eds.). "Observations: Oceanic Climate Change and Sea Level. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change" (PDF). Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Archived from the original (PDF) on 2017-05-13. Retrieved 2007-12-29.

[Gille_2002-7] Gille, Sarah T. (2002-02-15). "Warming of the Southern Ocean Since the 1950s". Science. 295 (5558): 1275–1277. Bibcode:2002Sci...295.1275G. doi:10.1126/science.1065863. PMID 11847337. S2CID 31434936.

[NOAA_2010_FAQ_b-8] "NOAA: NESDIS: NCDC: Frequently Asked Questions: How do we know the Earth's climate is warming?". NOAA. 2010-03-10.

[9] Bindoff, N. L.; Cheung, W. W. L.; Kairo, J. G.; Arístegui, J.; et al. (2019). "Chapter 5: Changing Ocean, Marine Ecosystems, and Dependent Communities" (PDF). IPCC SROCC 2019. p. 457. Archived (PDF) from the original on 28 May 2020. Retrieved 24 May 2020.

[10] Bindoff, N. L.; Cheung, W. W. L.; Kairo, J. G.; Arístegui, J.; et al. (2019). "Chapter 5: Changing Ocean, Marine Ecosystems, and Dependent Communities" (PDF). IPCC SROCC 2019. p. 457.^{[permanent dead link]}

[11] Bindoff, N. L.; Cheung, W. W. L.; Kairo, J. G.; Arístegui, J.; et al. (2019). "Chapter 5: Changing Ocean, Marine Ecosystems, and Dependent Communities" (PDF). IPCC SROCC 2019. p. 463. Archived (PDF) from the original on 20 December 2019. Retrieved 28 December 2019.

[Sea_level_rise_SROCC_SPM_20190925-12] IPCC, 2019: Summary for Policymakers. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D. C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N. M. Weyer (eds.)]. Cambridge University Press, Cambridge, UK and New York, New York, US. https://doi.org/10.1017/9781009157964.001.

[Sea_level_rise_WMO_20230421-13] "WMO annual report highlights continuous advance of climate change". World Meteorological Organization. 21 April 2023. Press Release Number: 21042023

[Sea_level_rise_IPCC_2021_WGI_SPM-14] IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J. B. R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, New York, US, pp. 3−32, doi:10.1017/9781009157896.001.

[Sea_level_rise_WCRP2018-15] WCRP Global Sea Level Budget Group (2018). "Global sea-level budget 1993–present". Earth System Science Data. 10 (3): 1551–1590. Bibcode:2018ESSD...10.1551W. doi:10.5194/essd-10-1551-2018. This corresponds to a mean sea-level rise of about 7.5 cm over the whole altimetry period. More importantly, the GMSL curve shows a net acceleration, estimated to be at 0.08mm/yr².

[Sea_level_rise_us_nrc_2011_long_term_slr-16] National Academies of Sciences, Engineering, and Medicine (2011). "Synopsis". Climate Stabilization Targets: Emissions, Concentrations, and Impacts over Decades to Millennia. Washington, DC: The National Academies Press. p. 5. doi:10.17226/12877. ISBN 978-0-309-15176-4. Box SYN-1: Sustained warming could lead to severe impacts

[Sea_level_rise_IPCC_AR6_WG1_Ch.9-17] Fox-Kemper, B.; Hewitt, Helene T.; Xiao, C.; Aðalgeirsdóttir, G.; Drijfhout, S. S.; Edwards, T. L.; Golledge, N. R.; Hemer, M.; Kopp, R. E.; Krinner, G.; Mix, A. (2021). Masson-Delmotte, V.; Zhai, P.; Pirani, A.; Connors, S. L.; Péan, C.; Berger, S.; Caud, N.; Chen, Y.; Goldfarb, L. (eds.). "Chapter 9: Ocean, Cryosphere and Sea Level Change" (PDF). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, NY, US.

[18] (Trujillo & Thurman 2008, p. 172)

[19] (Trujillo & Thurman 2008, p. 207)

[20] Talley, L. (2000). Sio 210 talley topic 5: North Atlantic circulation and water masses. thermohaline forcing.

[21] Roach, J. (2005, June 27). Global warming may alter atlantic currents, study says.

[Lenton_2008-22] Lenton, T. M.; Held, H.; Kriegler, E.; Hall, J. W.; Lucht, W.; Rahmstorf, S.; Schellnhuber, H. J. (2008). "Inaugural Article: Tipping elements in the Earth's climate system". Proceedings of the National Academy of Sciences. 105 (6): 1786–1793. Bibcode:2008PNAS..105.1786L. doi:10.1073/pnas.0705414105. PMC 2538841. PMID 18258748.

[IPCC_4th_assessment_h-23] IPCC (2007). M.L. Parry; et al. (eds.). Summary for Policymakers. In: Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (PDF). Cambridge, U.K., and New York, N.Y., U.S.A.: Cambridge University Press. pp. 7–22. Archived from the original (PDF) on 2018-01-13. Retrieved 2007-11-30.

[24] Carrington, Damian (5 August 2021). "Climate crisis: Scientists spot warning signs of Gulf Stream collapse". Guardian. Retrieved 6 August 2021.

[25] (Trujillo & Thurman 2008, p. 216)

[26] Canadell, J. G. et al (2007, November 01). Is the ocean carbon sink sinking?

[27] Webster, P. J. et al. (2005). Changes in tropical cyclone number, duration, and intensity in a warming environment.

[28] (Trujillo & Thurman 2008, p. 194)

[29] (Trujillo & Thurman 2008, p. 195)

[30] Renner, Jeff (1993). Northwest marine weather. the Mountaineers. pp. 71–72.

[31] Collier, Michael (2002). Floods, Droughts, and Climate Change. The University of Arizona Press. pp. 13–19.

[32] Archer, David (2009). The Long Thaw. Princeton University Press. pp. 69–77.

[33] Weller, Evan; Min, Seung-Ki; Cai, Wenju; Zwiers, Francis W.; Kim, Yeon-Hee; Lee, Donghyun (July 2016). "Human-caused Indo-Pacific warm pool expansion". Science Advances. 2 (7): e1501719. Bibcode:2016SciA....2E1719W. doi:10.1126/sciadv.1501719. ISSN 2375-2548. PMC 4942332. PMID 27419228.

[34] Roxy, M. K.; Dasgupta, Panini; McPhaden, Michael J.; Suematsu, Tamaki; Zhang, Chidong; Kim, Daehyun (November 2019). "Twofold expansion of the Indo-Pacific warm pool warps the MJO life cycle". Nature. 575 (7784): 647–651. Bibcode:2019Natur.575..647R. doi:10.1038/s41586-019-1764-4. ISSN 0028-0836. OSTI 1659516. PMID 31776488. S2CID 208329374.

[Tripati-Lab5-35] Tripati, Aradhna, Lab 5-Ocean pH, Ocean pH Reading, E&SSCI15-1, UCLA, 2012

[36] University Of Wyoming (2004, January 13). 2004/01/040113080810.htm Ocean Floor Reveals Clues To Global Warming. ScienceDaily. Retrieved May 21, 2012

[37] Pohlman, John W.; Greinert, Jens; Ruppel, Carolyn; Silyakova, Anna; Vielstadte, Lisa; Casso, Michael; Mienert, Jurgen; Bunz, Stefan (May 8, 2017). "Enhanced CO2 uptake at a shallow Arctic Ocean seep field overwhelms the positive warming potential of emitted methane". PNAS. 114 (21): 5355–5360. Bibcode:2017PNAS..114R5355P. doi:10.1073/pnas.1618926114. PMC 5448205. PMID 28484018.

[Ocean_acidification_role-38] Terhaar, Jens; Frölicher, Thomas L.; Joos, Fortunat (2023). "Ocean acidification in emission-driven temperature stabilization scenarios: the role of TCRE and non-CO₂ greenhouse gases". Environmental Research Letters. 18 (2): 024033. Bibcode:2023ERL....18b4033T. doi:10.1088/1748-9326/acaf91. ISSN 1748-9326. S2CID 255431338. Figure 1f

[Ocean_acidification_raven05-39] Ocean acidification due to increasing atmospheric carbon dioxide (PDF). Royal Society. 2005. ISBN 0-85403-617-2.

[Ocean_acidification_Jian2019-40] Jiang, Li-Qing; Carter, Brendan R.; Feely, Richard A.; Lauvset, Siv K.; Olsen, Are (2019). "Surface ocean pH and buffer capacity: past, present and future". Scientific Reports. 9 (1): 18624. Bibcode:2019NatSR...918624J. doi:10.1038/s41598-019-55039-4. PMC 6901524. PMID 31819102. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License Archived 16 October 2017 at the Wayback Machine

[41] Zhang, Y.; Yamamoto-Kawai, M.; Williams, W.J. (2020-02-16). "Two Decades of Ocean Acidification in the Surface Waters of the Beaufort Gyre, Arctic Ocean: Effects of Sea Ice Melt and Retreat From 1997–2016". Geophysical Research Letters. 47 (3). doi:10.1029/2019GL086421. S2CID 214271838.

[42] Beaupré-Laperrière, Alexis; Mucci, Alfonso; Thomas, Helmuth (2020-07-31). "The recent state and variability of the carbonate system of the Canadian Arctic Archipelago and adjacent basins in the context of ocean acidification". Biogeosciences. 17 (14): 3923–3942. Bibcode:2020BGeo...17.3923B. doi:10.5194/bg-17-3923-2020. S2CID 221369828.

[Ocean_deoxygenation_IUCN2019-43] Laffoley, D; Baxter, JM (2019). Ocean deoxygenation: everyone's problem. Switzerland: Gland. p. 562. ISBN 978-2-8317-2013-5.

[44] Limburg, Karin E.; Breitburg, Denise; Swaney, Dennis P.; Jacinto, Gil (2020-01-24). "Ocean Deoxygenation: A Primer". One Earth. 2 (1): 24–29. Bibcode:2020OEart...2...24L. doi:10.1016/j.oneear.2020.01.001. ISSN 2590-3330. S2CID 214348057.

[Ocean_deoxygenation_:1-45] Oschlies, Andreas; Brandt, Peter; Stramma, Lothar; Schmidtko, Sunke (2018). "Drivers and mechanisms of ocean deoxygenation". Nature Geoscience. 11 (7): 467–473. Bibcode:2018NatGe..11..467O. doi:10.1038/s41561-018-0152-2. ISSN 1752-0894. S2CID 135112478.

[Ocean_deoxygenation_Stramma-46] Stramma, L; Johnson, GC; Printall, J; Mohrholz, V (2008). "Expanding Oxygen-Minimum Zones in the Tropical Oceans". Science. 320 (5876): 655–658. Bibcode:2008Sci...320..655S. doi:10.1126/science.1153847. PMID 18451300. S2CID 206510856.

[Ocean_deoxygenation_Mora-47] Mora, C; et al. (2013). "Biotic and Human Vulnerability to Projected Changes in Ocean Biogeochemistry over the 21st Century". PLOS Biology. 11 (10): e1001682. doi:10.1371/journal.pbio.1001682. PMC 3797030. PMID 24143135.

[Ocean_deoxygenation_theguardian.com-48] Carrington (2018-01-04). "Environment. Oceans suffocating as huge dead zones quadruple since 1950, scientists warn". The Guardian. ISSN 0261-3077. Retrieved 2023-07-04.

[Ocean_deoxygenation_agupubs.onlinelibrary.wiley.com-49] Long, Matthew C.; Deutsch, Curtis; Ito, Taka (2016). "Finding forced trends in oceanic oxygen". Global Biogeochemical Cycles. 30 (2): 381–397. Bibcode:2016GBioC..30..381L. doi:10.1002/2015GB005310. ISSN 0886-6236. S2CID 130885459.

[Ocean_deoxygenation_carbonbrief.org-50] Pearce, Rosamund (2018-06-15). "Guest post: How global warming is causing ocean oxygen levels to fall". Carbon Brief. Retrieved 2023-07-04.

[Ocean_deoxygenation_Harvey-51] Harvey, Fiona (2019-12-07). "Oceans losing oxygen at unprecedented rate, experts warn". The Guardian. ISSN 0261-3077. Retrieved 2019-12-07.

[Ocean_deoxygenation_Laffoley2019-52] Laffoley, D. & Baxter, J.M. (eds.) (2019). Ocean deoxygenation: Everyone's problem - Causes, impacts, consequences and solutions. IUCN, Switzerland.

[53] Bednaršek, N., Harvey, C.J., Kaplan, I.C., Feely, R.A. and Možina, J. (2016) "Pteropods on the edge: Cumulative effects of ocean acidification, warming, and deoxygenation". Progress in Oceanography, 145: 1–24. doi:10.1016/j.pocean.2016.04.002

[54] Keeling, Ralph F., and Hernan E. Garcia (2002) "The change in oceanic O2 inventory associated with recent global warming." Proceedings of the National Academy of Sciences, 99(12): 7848–7853. doi:10.1073/pnas.122154899

[feeley08-55] Feely, R. A.; Sabine, C. L.; Hernandez-Ayon, J. M.; Ianson, D.; Hales, B. (2008). "Evidence for Upwelling of Corrosive "Acidified" Water onto the Continental Shelf". Science. 320 (5882): 1490–2. Bibcode:2008Sci...320.1490F. CiteSeerX 10.1.1.328.3181. doi:10.1126/science.1155676. PMID 18497259. S2CID 35487689.

[56] Zeebe, Richard E.; Wolf-Gladrow, D. (2001). CO2 in seawater : equilibrium, kinetics, isotopes. Amsterdam. p. 346. ISBN 9780444509468.{{cite book}}: CS1 maint: location missing publisher (link)

[57] Dai, Minhan; Cao, Zhimian; Guo, Xianghui; Zhai, Weidong; Liu, Zhiyu; Yin, Zhiqiang; Xu, Yanping; Gan, Jianping; Hu, Jianyu; Du, Chuanjun (28 May 2013). "Why are some marginal seas sources of atmospheric CO2 ?: SOME MARGINAL SEAS ARE CO2 SOURCES". Geophysical Research Letters. 40 (10): 2154–2158. doi:10.1002/grl.50390.

[58] Sisma-Ventura, Guy; Bialik, Or M.; Yam, Ruth; Herut, Barak; Silverman, Jacob (November 2017). "p CO 2 variability in the surface waters of the ultra-oligotrophic Levantine Sea: Exploring the air–sea CO 2 fluxes in a fast warming region". Marine Chemistry. 196: 13–23. doi:10.1016/j.marchem.2017.06.006.

[Milkov_2004-59] Milkov, A. V. (2004). "Global estimates of hydrate-bound gas in marine sediments: How much is really out there?". Earth-Science Reviews. 66 (3–4): 183–197. Bibcode:2004ESRv...66..183M. doi:10.1016/j.earscirev.2003.11.002.

[60] The oceans occupy 361 million sq km

[USGS_2000-61] USGS World Energy Assessment Team, 2000. US Geological Survey world petroleum assessment 2000––description and results. USGS Digital Data Series DDS-60

[Roxy2016-62] Roxy, M.K. (2016). "A reduction in marine primary productivity driven by rapid warming over the tropical Indian Ocean" (PDF). Geophysical Research Letters. 43 (2): 826–833. Bibcode:2016GeoRL..43..826R. doi:10.1002/2015GL066979.

[Behrenfeld_et_al_2006-63] Behrenfeld, Michael J.; O'Malley, Robert T.; Siegel, David A.; McClain, Charles R.; Sarmiento, Jorge L.; Feldman, Gene C.; Milligan, Allen J.; Falkowski, Paul G.; Letelier, Ricardo M.; Boss, Emmanuel S. (December 2006). "Climate-driven trends in contemporary ocean productivity". Nature. 444 (7120): 752–755. Bibcode:2006Natur.444..752B. doi:10.1038/nature05317. PMID 17151666. S2CID 4414391.

[:0-64] "Marine pollution, explained". National Geographic. 2019-08-02. Retrieved 2020-04-07.

[:10-65] Humphreys, M. P. (2016). "Climate sensitivity and the rate of ocean acidification: future impacts, and implications for experimental design". ICES Journal of Marine Science. 74 (4): 934–940. doi:10.1093/icesjms/fsw189.

[66] "Sustainable Seafood | Industries | WWF". World Wildlife Fund. Retrieved 2020-04-07.

[67] "What is a pescatarian diet?". BBC Good Food. Retrieved 2020-04-07.

[68] Chappelow, Jim. "Learn about Law of Supply and Demand". Investopedia. Retrieved 2020-04-07.

[69] Vaughan, Adam (2 July 2020). "Climate change will make world too hot for 60 per cent of fish species". New Scientist. Retrieved 3 July 2020.

[70] Buchheim, Jason "Coral Reef Bleaching," Odyssey Expeditions Tropical Marine Biology Voyages

[71] "Harmful Algal Blooms: Simple Plants with Toxic Implications," National Oceanic and Atmospheric Administration.

[72] Observations: Oceanic Climate Change and Sea Level Archived 2017-05-13 at the Wayback Machine In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. (15 MB).

[73] Doney, S. C. (March 2006). "The Dangers of Ocean Acidification" (PDF). Scientific American. 294 (3): 58–65. Bibcode:2006SciAm.294c..58D. doi:10.1038/scientificamerican0306-58. PMID 16502612.

[74] US EPA, OAR (2015-04-07). "Climate Action Benefits: Freshwater Fish". US EPA. Retrieved 2020-04-06.

[Climate_change_and_fisheries_:03-75] Weatherdon, Lauren V.; Magnan, Alexandre K.; Rogers, Alex D.; Sumaila, U. Rashid; Cheung, William W. L. (2016). "Observed and Projected Impacts of Climate Change on Marine Fisheries, Aquaculture, Coastal Tourism, and Human Health: An Update". Frontiers in Marine Science. 3. doi:10.3389/fmars.2016.00048. ISSN 2296-7745.

[76] Cheung, W.W.L.; et al. (October 2009). Redistribution of Fish Catch by Climate Change. A Summary of a New Scientific Analysis (PDF). Sea Around Us (Report). Archived from the original (PDF) on 2011-07-26.

[Climate_change_and_fisheries_:7-77] Manuel Barange; Tarûb Bahri; Malcolm C. M. Beveridge; K. L. Cochrane; S. Funge Smith; Florence Poulain, eds. (2018). Impacts of climate change on fisheries and aquaculture: synthesis of current knowledge, adaptation and mitigation options. Rome: Food and Agriculture Organization of the United Nations. ISBN 978-92-5-130607-9. OCLC 1078885208.

[Climate_change_and_fisheries_:1-78] Intergovernmental Panel on Climate Change (IPCC), ed. (2022), "Sea Level Rise and Implications for Low-Lying Islands, Coasts and Communities", The Ocean and Cryosphere in a Changing Climate: Special Report of the Intergovernmental Panel on Climate Change, Cambridge: Cambridge University Press, pp. 321–446, doi:10.1017/9781009157964.006, ISBN 978-1-00-915796-4, S2CID 246522316, retrieved 2022-04-06

[79] Burek, Kathy A.; Gulland, Frances M. D.; O'Hara, Todd M. (2008). "Effects of Climate Change on Arctic Marine Mammal Health" (PDF). Ecological Applications. 18 (2): S126–S134. doi:10.1890/06-0553.1. ISSN 1051-0761. JSTOR 40062160. PMID 18494366.

[:02-80] Albouy, Camille; Delattre, Valentine; Donati, Giulia; Frölicher, Thomas L.; Albouy-Boyer, Severine; Rufino, Marta; Pellissier, Loïc; Mouillot, David; Leprieur, Fabien (December 2020). "Global vulnerability of marine mammals to global warming". Scientific Reports. 10 (1): 548. Bibcode:2020NatSR..10..548A. doi:10.1038/s41598-019-57280-3. ISSN 2045-2322. PMC 6969058. PMID 31953496.

[81] Avila, Isabel C.; Kaschner, Kristin; Dormann, Carsten F. (May 2018). "Current global risks to marine mammals: Taking stock of the threats". Biological Conservation. 221: 44–58. doi:10.1016/j.biocon.2018.02.021. ISSN 0006-3207.

[dx.doi.org-82] Stirling, Ian; Lunn, Nicholas J.; Iacozza, John (1999-01-01). "Long-term Trends in the Population Ecology of Polar Bears in Western Hudson Bay in Relation to Climatic Change". Arctic. 52 (3). doi:10.14430/arctic935. ISSN 1923-1245.

[T._2013-83] T., DeWeaver, Eric (2013). Arctic Sea Ice Decline : Observations, Projections, Mechanisms, and Implications. Wiley. ISBN 978-1-118-67158-0. OCLC 850080201.{{cite book}}: CS1 maint: multiple names: authors list (link)

[84] Malcolm., Penny (2000). Polar bear : habitats, life cycles, food chains, threats. Raintree Steck-Vaughn Publishers. ISBN 0-7398-1060-X. OCLC 41565047.

[85] D.), Tarbox, A. D. (Angelique (2009). An Arctic tundra food chain. Creative Education. ISBN 978-1-58341-596-2. OCLC 78072263.{{cite book}}: CS1 maint: multiple names: authors list (link)

[86] Michael., Pagano, Anthony (2018). Polar Bear (Ursus maritimus) Behavior and Energetics : New Metrics for Examining the Physiological Impact of a Changing Arctic Environment. ISBN 978-0-438-24947-9. OCLC 1076545435.{{cite book}}: CS1 maint: multiple names: authors list (link)

[87] V., Regehr, Eric (2006). Polar bear population status in the southern Beaufort Sea. U.S. Geological Survey. OCLC 76881605.{{cite book}}: CS1 maint: multiple names: authors list (link)

[88] Riddihough, G. (2010-03-18). "Polar Bear, Polar Bear". Science. 327 (5972): 1430–1431. Bibcode:2010Sci...327.1430R. doi:10.1126/science.327.5972.1430-d. ISSN 0036-8075.

[:5-89] Würsig, Bernd; Reeves, Randall R.; Ortega-Ortiz, J. G. (2001), Evans, Peter G. H.; Raga, Juan Antonio (eds.), "Global Climate Change and Marine Mammals", Marine Mammals: Biology and Conservation, Boston, MA: Springer US, pp. 589–608, doi:10.1007/978-1-4615-0529-7_17, ISBN 978-1-4615-0529-7, retrieved 2021-05-01

[90] Salvadeo, CJ; Lluch-Belda, D; Gómez-Gallardo, A; Urbán-Ramírez, J; MacLeod, CD (2010-03-10). "Climate change and a poleward shift in the distribution of the Pacific white-sided dolphin in the northeastern Pacific". Endangered Species Research. 11 (1): 13–19. doi:10.3354/esr00252. ISSN 1863-5407.

[91] Cañadas, A.; Vázquez, J.A. (2017-07-01). "Common dolphins in the Alboran Sea: Facing a reduction in their suitable habitat due to an increase in Sea surface temperature". Deep Sea Research Part II: Topical Studies in Oceanography. 141: 306–318. Bibcode:2017DSRII.141..306C. doi:10.1016/j.dsr2.2017.03.006. ISSN 0967-0645.

[:6-92] Evans, Peter G.H.; Bjørge, Arne (November 28, 2013). "Impacts of climate change on marine mammals" (PDF). MCCIP Science Review 2013.

[93] MacLeod, Colin D.; Bannon, Sarah M.; Pierce, Graham J.; Schweder, Caroline; Learmonth, Jennifer A.; Herman, Jerry S.; Reid, Robert J. (2005-08-01). "Climate change and the cetacean community of north-west Scotland". Biological Conservation. 124 (4): 477–483. doi:10.1016/j.biocon.2005.02.004. ISSN 0006-3207.

[:7-94] Gomez-Salazar, Catalina; Coll, Marta; Whitehead, Hal (2012-12-01). "River dolphins as indicators of ecosystem degradation in large tropical rivers". Ecological Indicators. 23: 19–26. doi:10.1016/j.ecolind.2012.02.034. ISSN 1470-160X.

[95] Wild, Sonja; Krützen, Michael; Rankin, Robert W.; Hoppitt, William J.E.; Gerber, Livia; Allen, Simon J. (2019-04-01). "Long-term decline in survival and reproduction of dolphins following a marine heatwave". Current Biology. 29 (7): R239–R240. doi:10.1016/j.cub.2019.02.047. ISSN 0960-9822. PMID 30939303.

[Hardwood-96] Harwood, John (1 August 2001). "Marine mammals and their environment in the twenty-first century". Journal of Mammalogy. 82 (3): 630–640. doi:10.1644/1545-1542(2001)082<0630:MMATEI>2.0.CO;2. ISSN 0022-2372.

[Simmonds-97] Simmonds, Mark P.; Isaac, Stephen J. (5 March 2007). "The impacts of climate change on marine mammals: early signs of significant problems". Oryx. 41 (1): 19–26. doi:10.1017/s0030605307001524.

[Tynan-98] Tynan, Cynthia T.; DeMaster, Douglas P. (1997). "Observations and Predictions of Arctic Climatic Change: Potential Effects on Marine Mammals" (PDF). Arctic. 50 (4): 308–322. doi:10.14430/arctic1113. Animals have a high risk of mortality.

[Learmonth-99] Learmonth, JA; Macleod, CD; Santos, MB; Pierce, GJ; Crick, HQP; Robinson, RA (2006). "Potential effects of climate change on marine mammals". In Gibson, RN; Atkinson, RJA; Gordon, JDM (eds.). Oceanography and marine biology an annual review. Volume 44. Boca Raton: Taylor & Francis. pp. 431–464. ISBN 9781420006391.

[100] Laidre, Kristin L.; Stirling, Ian; Lowry, Lloyd F.; Wiig, Øystein; Heide-Jørgensen, Mads Peter; Ferguson, Steven H. (January 1, 2008). "Quantifying the Sensitivity of Arctic Marine Mammals to Climate-Induced Habitat Change". Ecological Applications. 18 (2): S97–S125. doi:10.1890/06-0546.1. JSTOR 40062159. PMID 18494365.

[101] Map Shows Vast Regions of Ocean Are Warmer March 30, 2013 Scientific American

[102] Cheng, Lijing; Abraham, John; Zhu, Jiang; Trenberth, Kevin E.; Fasullo, John; Boyer, Tim; Locarnini, Ricardo; Zhang, Bin; Yu, Fujiang; Wan, Liying; Chen, Xingrong (February 2020). "Record-Setting Ocean Warmth Continued in 2019". Advances in Atmospheric Sciences. 37 (2): 137–142. Bibcode:2020AdAtS..37..137C. doi:10.1007/s00376-020-9283-7. ISSN 0256-1530. S2CID 210157933.

[:1-103] Yao, Cui-Luan; Somero, George N. (February 2014). "The impact of ocean warming on marine organisms". Chinese Science Bulletin. 59 (5–6): 468–479. Bibcode:2014ChSBu..59..468Y. doi:10.1007/s11434-014-0113-0. ISSN 1001-6538. S2CID 98449170.

[104] Glick, Patrick; Clough, Jonathan; Nunley, Brad. "Sea-Level Rise and Coastal Habitats in the Chesapeake Bay Region" (PDF). National Wildlife Federation. Retrieved November 8, 2014.

[105] Sarmento, H.; Montoya, JM.; Vázquez-Domínguez, E.; Vaqué, D.; Gasol, JM. (2010). "Warming effects on marine microbial food web processes: how far can we go when it comes to predictions?". Philosophical Transactions of the Royal Society B: Biological Sciences. 365 (1549): 2137–2149. doi:10.1098/rstb.2010.0045. PMC 2880134. PMID 20513721.

[106] Vázquez-Domínguez, E.; Vaqué, D.; Gasol, JM. (2007). "Ocean warming enhances respiration and carbon demand of coastal microbial plankton". Global Change Biology. 13 (7): 1327–1334. Bibcode:2007GCBio..13.1327V. doi:10.1111/j.1365-2486.2007.01377.x. hdl:10261/15731.

[107] Vázquez-Domínguez, E.; Vaqué, D.; Gasol, JM. (2012). "Temperature effects on the heterotrophic bacteria, heterotrophic nanoflagellates, and microbial top predators of NW Mediterranean". Aquatic Microbial Ecology. 67 (2): 107–121. doi:10.3354/ame01583.

[108] Mazuecos, E.; Arístegui, J.; Vázquez-Domínguez, E.; Ortega-Retuerta, E.; Gasol, JM.; Reche, I. (2012). "Temperature control of microbial respiration and growth efficiency in the mesopelagic zone of the South Atlantic and Indian Oceans". Deep Sea Research Part I: Oceanographic Research Papers. 95 (2): 131–138. doi:10.3354/ame01583.

[109] Castilla, Juan Carlos. "Marine Ecosystems, Human Impacts on". Encyclopedia of Biodiversity (2 ed.). Academic Press. pp. 56–63.

[110] Haldar, Ishita (30 April 2018). Global Warming: The Causes and Consequences. Readworthy. ISBN 9788193534571.

[:2-111] Euzen, Agathe (2017). The ocean revealed. Paris: CNRS ÉDITIONS. ISBN 978-2-271-11907-0.

[112] Derocher, A. E. (2004-04-01). "Polar Bears in a Warming Climate". Integrative and Comparative Biology. 44 (2): 163–176. doi:10.1093/icb/44.2.163. ISSN 1540-7063. PMID 21680496. S2CID 13716867.

[113] Burek, Kathy A.; Gulland, Frances M. D.; O'Hara, Todd M. (March 2008). "Effects of Climate Change on Arctic Marine Mammal Health". Ecological Applications. 18 (sp2): S126–S134. doi:10.1890/06-0553.1. ISSN 1051-0761. PMID 18494366.

[:3-114] Ekau, W.; Auel, H.; Pörtner, H.-O.; Gilbert, D. (2010-05-21). "Impacts of hypoxia on the structure and processes in pelagic communities (zooplankton, macro-invertebrates and fish)". Biogeosciences. 7 (5): 1669–1699. Bibcode:2010BGeo....7.1669E. doi:10.5194/bg-7-1669-2010. ISSN 1726-4189.

[:4-115] Conley, Daniel J.; Björck, Svante; Bonsdorff, Erik; Carstensen, Jacob; Destouni, Georgia; Gustafsson, Bo G.; Hietanen, Susanna; Kortekaas, Marloes; Kuosa, Harri; Markus Meier, H. E.; Müller-Karulis, Baerbel (2009-05-15). "Hypoxia-Related Processes in the Baltic Sea". Environmental Science & Technology. 43 (10): 3412–3420. Bibcode:2009EnST...43.3412C. doi:10.1021/es802762a. ISSN 0013-936X. PMID 19544833.

[116] Conley*, Daniel J.; Bonsdorff, Erik; Carstensen, Jacob; Destouni, Georgia; Gustafsson, Bo G.; Hansson, Lars-Anders; Rabalais, Nancy N.; Voss, Maren; Zillén, Lovisa (2009-05-15). "Tackling Hypoxia in the Baltic Sea: Is Engineering a Solution?". Environmental Science & Technology. 43 (10): 3407–3411. Bibcode:2009EnST...43.3407C. doi:10.1021/es8027633. ISSN 0013-936X. PMID 19544832.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

[19]

[20]

[21]

[22]

[23]

[24]

[25]

[26]

[27]

[28]

[29]

[30]

[31]

[32]

[33]

[34]

[35]

[36]

[37]

[38]

[39]

[40]

[41]

[42]

[43]

[44]

[45]

[46]

[47]

[48]

[49]

[50]

[51]

[52]

[53]

[54]

[55]

[56]

[57]

[58]

[59]

[60]

[61]

[62]

[63]

[64]

[65]

[66]

[67]

[68]

[69]

[70]

[71]

[72]

[73]

[74]

[75]

[76]

[77]

[78]

[79]

[80]

[81]

[82]

[83]

[84]

[85]

[86]

[87]

[88]

[89]

[90]

[91]

[92]

[93]

[94]

[95]

[96]

[97]

[98]

[99]

[100]

@@ Line 169: / Line 169: @@
 ==Effects on fisheries==
 {{excerpt|Effects of climate change on fisheries|paragraphs=1-2|file=no}}
+== Effects on marine life and mammals ==
+{{short description|Direct and indirect effects}}
+The effect of climate change on marine life and mammals is a growing concern. Many of the [[effects of global warming]] are currently unknown due to unpredictability, but many are becoming increasingly evident today. Some effects are very direct such as [[Habitat destruction|loss of habitat]], temperature stress, and exposure to severe weather. Other effects are more indirect, such as changes in host pathogen associations, changes in body condition because of predator–prey interaction, changes in exposure to toxins and {{CO2}} emissions, and increased human interactions.<ref>{{cite journal |last1=Burek |first1=Kathy A. |last2=Gulland |first2=Frances M. D. |last3=O'Hara |first3=Todd M. |date=2008 |title=Effects of Climate Change on Arctic Marine Mammal Health |url=http://www.marinemammalcenter.org/assets/pdfs/vetsci-stranding/scientific-contributions/2008/burek-2008-effect-of-climate.pdf |journal=Ecological Applications |volume=18 |issue=2 |pages=S126–S134 |doi=10.1890/06-0553.1 |issn=1051-0761 |jstor=40062160 |pmid=18494366 |doi-access=free}}</ref>  Despite the large potential impacts of ocean warming on marine mammals, the global vulnerability of marine mammals to global warming is still poorly understood.<ref name=":02">{{Cite journal |last1=Albouy |first1=Camille |last2=Delattre |first2=Valentine |last3=Donati |first3=Giulia |last4=Frölicher |first4=Thomas L. |last5=Albouy-Boyer |first5=Severine |last6=Rufino |first6=Marta |last7=Pellissier |first7=Loïc |last8=Mouillot |first8=David |last9=Leprieur |first9=Fabien |date=December 2020 |title=Global vulnerability of marine mammals to global warming |url= |journal=Scientific Reports |language=en |volume=10 |issue=1 |pages=548 |bibcode=2020NatSR..10..548A |doi=10.1038/s41598-019-57280-3 |issn=2045-2322 |pmc=6969058 |pmid=31953496}}</ref>
+It has been generally assumed that the Arctic marine mammals were the most vulnerable in the face of climate change given the substantial observed and projected decline in [[Arctic sea ice]] cover. However, the implementation of a trait-based approach on assessment of the vulnerability of all marine mammals under future global warming has suggested that the [[North Pacific Ocean]], the [[Greenland Sea]] and the [[Barents Sea]] host the species that are most vulnerable to global warming.<ref name=":02" />  The North Pacific has already been identified as a hotspot for human threats for marine mammals<ref>{{Cite journal |last1=Avila |first1=Isabel C. |last2=Kaschner |first2=Kristin |last3=Dormann |first3=Carsten F. |date=May 2018 |title=Current global risks to marine mammals: Taking stock of the threats |url=http://dx.doi.org/10.1016/j.biocon.2018.02.021 |journal=Biological Conservation |volume=221 |pages=44–58 |doi=10.1016/j.biocon.2018.02.021 |issn=0006-3207}}</ref> and now is also a hotspot of vulnerability to global warming. This emphasizes that marine mammals in this region will face double jeopardy from both human activities (e.g., marine traffic, pollution and offshore oil and gas development) and global warming, with potential additive or synergetic effect and as a result, these [[Ecosystem|ecosystems]] face irreversible consequences for marine ecosystem functioning.<ref name=":02" />
+=== Species impacted ===
+==== Polar bears ====
+[[File:Polar_bear_waiting.jpg|thumb|A polar bear waiting in the Fall for the sea ice to form.]]
+[[Polar bears]] are one of many Arctic marine mammals at risk of population decline due to [[climate change]].<ref name="dx.doi.org">{{Cite journal |last1=Stirling |first1=Ian |last2=Lunn |first2=Nicholas J. |last3=Iacozza |first3=John |date=1999-01-01 |title=Long-term Trends in the Population Ecology of Polar Bears in Western Hudson Bay in Relation to Climatic Change |url=http://dx.doi.org/10.14430/arctic935 |journal=Arctic |volume=52 |issue=3 |doi=10.14430/arctic935 |issn=1923-1245}}</ref> When [[carbon dioxide]] is released into the [[atmosphere]], a [[Greenhouse gas|greenhouse]] like effect occurs, warming the climate. For polar bears and other Arctic marine mammals, rising temperature is the changing the sea ice formations that they rely on to survive.<ref name="dx.doi.org" /> In the circumpolar north, the [[Arctic ice pack|Arctic sea ice]] is a dynamic [[ecosystem]]. The levels of sea ice extent varies by season. While some areas maintain year-round ice, others only have ice on a seasonal basis. The amount of permanent sea ice is decreasing with global temperature increases. Climate change is causing slower formations of sea ice, quicker decline and thinner ice sheets. Polar bears and other Arctic marine mammals are losing their habitat and food sources in result of the sea ice decline.<ref name="T. 2013">{{Cite book |last=T. |first=DeWeaver, Eric |url=http://worldcat.org/oclc/850080201 |title=Arctic Sea Ice Decline : Observations, Projections, Mechanisms, and Implications. |date=2013 |publisher=Wiley |isbn=978-1-118-67158-0 |oclc=850080201}}</ref>
+Polar bears rely on [[Fur seal|seals]] as their main food source.<ref>{{Cite book |last=Malcolm. |first=Penny |url=http://worldcat.org/oclc/41565047 |title=Polar bear : habitats, life cycles, food chains, threats |date=2000 |publisher=Raintree Steck-Vaughn Publishers |isbn=0-7398-1060-X |oclc=41565047}}</ref> Although polar bears are strong swimmers, they are not successful at catching seal underwater, therefore polar bears are ambush predators.<ref>{{Cite book |last=D.) |first=Tarbox, A. D. (Angelique |url=http://worldcat.org/oclc/78072263 |title=An Arctic tundra food chain |date=2009 |publisher=Creative Education |isbn=978-1-58341-596-2 |oclc=78072263}}</ref> When they hunt seals, they wait at seal breathing hole to ambush and haul out their prey onto the sea ice for feeding. With slower sea ice formations, thinner ice sheets and shorter winter seasons, polar bears are having less opportunity for optimal hunting grounds. Polar bears are facing pressures to swim further to gain access to food. This requires more calories spent to obtain calories to sustain their body conditions for reproduction and survival. Researchers use body condition charts to track polar bear population health and reproductive potential.<ref>{{Cite book |last=Michael. |first=Pagano, Anthony |url=http://worldcat.org/oclc/1076545435 |title=Polar Bear (Ursus maritimus) Behavior and Energetics : New Metrics for Examining the Physiological Impact of a Changing Arctic Environment. |year=2018 |isbn=978-0-438-24947-9 |oclc=1076545435}}</ref> Trends suggest 12 out of 19 sub populations of polar bears are declining or data deficient.<ref>{{Cite book |last=V. |first=Regehr, Eric |url=http://worldcat.org/oclc/76881605 |title=Polar bear population status in the southern Beaufort Sea |date=2006 |publisher=U.S. Geological Survey |oclc=76881605}}</ref>
+Polar bears also rely on sea ice to travel, mate and female polar bears usually choose to den up on the sea ice during denning season.<ref>{{Cite journal |last=Riddihough |first=G. |date=2010-03-18 |title=Polar Bear, Polar Bear |journal=Science |volume=327 |issue=5972 |pages=1430–1431 |bibcode=2010Sci...327.1430R |doi=10.1126/science.327.5972.1430-d |issn=0036-8075 |doi-access=free}}</ref> The sea ice is becoming less stable, forcing pregnant female polar bears to choose less optimal locations for denning.<ref name="T. 2013" /> These aspects are known to result in lower reproduction rates and smaller cub years.
+==== Dolphins ====
+[[Dolphin|Dolphins]] are marine mammals with broad geographic extent, making them susceptible to climate change in various ways. The most common effect of climate change on dolphins is the increasing water temperatures across the globe. This has caused a large variety of dolphin species to experience range shifts, in which the species move from their typical geographic region to warmer waters.
+In [[California]], the 1982-83 [[El Niño]] warming event caused the near-bottom spawning [[market squid]] to leave southern California, which caused their predator, the [[pilot whale]], to also leave. As the market squid returned six years later, [[Risso's dolphin|Risso's dolphins]] came to feed on the squid. [[Bottlenose dolphin|Bottlenose dolphins]] expanded their range from southern to central California, and stayed even after the warming event subsided.<ref name=":5">{{Citation |last1=Würsig |first1=Bernd |title=Global Climate Change and Marine Mammals |date=2001 |url=https://doi.org/10.1007/978-1-4615-0529-7_17 |work=Marine Mammals: Biology and Conservation |pages=589–608 |editor-last=Evans |editor-first=Peter G. H. |place=Boston, MA |publisher=Springer US |language=en |doi=10.1007/978-1-4615-0529-7_17 |isbn=978-1-4615-0529-7 |access-date=2021-05-01 |last2=Reeves |first2=Randall R. |last3=Ortega-Ortiz |first3=J. G. |editor2-last=Raga |editor2-first=Juan Antonio}}</ref> The [[Pacific white-sided dolphin]] has had a decline in population in the southwest [[Gulf of California]], the southern boundary of their distribution. In the 1980s they were abundant with group sizes up to 200 across the entire cool season. Then, in the 2000s, only two groups were recorded with sizes of 20 and 30, and only across the central cool season. This decline was not related to a decline of other marine mammals or prey, so it was concluded to have been caused by climate change as it occurred during a period of warming. Additionally, the Pacific white-sided dolphin had an increase in occurrence on the west coast of [[Canada]] from 1984 to 1998.<ref>{{Cite journal |last1=Salvadeo |first1=CJ |last2=Lluch-Belda |first2=D |last3=Gómez-Gallardo |first3=A |last4=Urbán-Ramírez |first4=J |last5=MacLeod |first5=CD |date=2010-03-10 |title=Climate change and a poleward shift in the distribution of the Pacific white-sided dolphin in the northeastern Pacific |url=https://www.int-res.com/abstracts/esr/v11/n1/p13-19/ |journal=Endangered Species Research |language=en |volume=11 |issue=1 |pages=13–19 |doi=10.3354/esr00252 |issn=1863-5407 |doi-access=free}}</ref>
+In the [[Mediterranean]], [[Sea surface temperature|sea surface temperatures]] have increased, as well as [[salinity]], [[upwelling]] intensity, and sea levels. Because of this, prey resources have been reduced causing a steep decline in the [[short-beaked common dolphin]] Mediterranean subpopulation, which was deemed endangered in 2003. This species now only exists in the [[Alboran Sea]], due to its high productivity, distinct ecosystem, and differing conditions from the rest of the Mediterranean.<ref>{{Cite journal |last1=Cañadas |first1=A. |last2=Vázquez |first2=J.A. |date=2017-07-01 |title=Common dolphins in the Alboran Sea: Facing a reduction in their suitable habitat due to an increase in Sea surface temperature |url=https://www.sciencedirect.com/science/article/abs/pii/S0967064517300656 |journal=Deep Sea Research Part II: Topical Studies in Oceanography |language=en |volume=141 |pages=306–318 |bibcode=2017DSRII.141..306C |doi=10.1016/j.dsr2.2017.03.006 |issn=0967-0645 |doi-access=free}}</ref>
+In northwest Europe, many dolphin species have experienced range shifts from the region’s typically colder waters. Warm water dolphins, like the short-beaked common dolphin and [[striped dolphin]], have expanded north of western Britain and into the northern [[North Sea]], even in the winter, which may displace the [[White-beaked dolphin|white-beaked]] and [[Atlantic white-sided dolphin]] that are in that region. The white-beaked dolphin has shown an increase in the southern North Sea since the 1960s because of this. The [[rough-toothed dolphin]] and [[Atlantic spotted dolphin]] may move to northwest Europe.<ref name=":6">{{Cite journal |last1=Evans |first1=Peter G.H. |last2=Bjørge |first2=Arne |date=November 28, 2013 |title=Impacts of climate change on marine mammals |url=https://www.seawatchfoundation.org.uk/wp-content/uploads/2015/05/Evans-Bj%C3%B8rge_2013.pdf |journal=MCCIP Science Review 2013}}</ref> In northwest [[Scotland]], white-beaked dolphins (local to the colder waters of the North Atlantic) have decreased while common dolphins (local to warmer waters) have increased from 1992-2003.<ref>{{Cite journal |last1=MacLeod |first1=Colin D. |last2=Bannon |first2=Sarah M. |last3=Pierce |first3=Graham J. |last4=Schweder |first4=Caroline |last5=Learmonth |first5=Jennifer A. |last6=Herman |first6=Jerry S. |last7=Reid |first7=Robert J. |date=2005-08-01 |title=Climate change and the cetacean community of north-west Scotland |url=https://www.sciencedirect.com/science/article/abs/pii/S0006320705000789 |journal=Biological Conservation |language=en |volume=124 |issue=4 |pages=477–483 |doi=10.1016/j.biocon.2005.02.004 |issn=0006-3207}}</ref> Additionally, [[Fraser's dolphin|Fraser’s dolphin]], found in tropical waters, was recorded in the UK for the first time in 1996.<ref name=":6" />
+[[River dolphin|River dolphins]] are highly affected by climate change as high evaporation rates, increased water temperatures, decreased precipitation, and increased [[Ocean acidification|acidification]] occur.<ref name=":5" /><ref name=":7">{{Cite journal |last1=Gomez-Salazar |first1=Catalina |last2=Coll |first2=Marta |last3=Whitehead |first3=Hal |date=2012-12-01 |title=River dolphins as indicators of ecosystem degradation in large tropical rivers |url=https://www.sciencedirect.com/science/article/abs/pii/S1470160X12000805 |journal=Ecological Indicators |language=en |volume=23 |pages=19–26 |doi=10.1016/j.ecolind.2012.02.034 |issn=1470-160X}}</ref> River dolphins typically have a higher densities when rivers have a lox index of freshwater degradation and better water quality.<ref name=":7" /> Specifically looking at the [[Ganges river dolphin]], the high evaporation rates and increased flooding on the plains may lead to more human river regulation, decreasing the dolphin population.<ref name=":5" />
+As warmer waters lead to a decrease in dolphin prey, this led to other causes of dolphin population decrease. In the case of bottlenose dolphins, [[Mullet (fish)|mullet]] populations decrease due to increasing water temperatures, which leads to a decrease in the dolphins’ health and thus their population.<ref name=":5" /> At the Shark Bay World Heritage Area in Western Australia, the local [[Indo-Pacific bottlenose dolphin]] population had a significant decline after a marine heatwave in 2011. This heatwave caused a decrease in prey, which led to a decline in dolphin reproductive rates as female dolphins could not get enough nutrients to sustain a calf.<ref>{{Cite journal |last1=Wild |first1=Sonja |last2=Krützen |first2=Michael |last3=Rankin |first3=Robert W. |last4=Hoppitt |first4=William J.E. |last5=Gerber |first5=Livia |last6=Allen |first6=Simon J. |date=2019-04-01 |title=Long-term decline in survival and reproduction of dolphins following a marine heatwave |journal=Current Biology |language=en |volume=29 |issue=7 |pages=R239–R240 |doi=10.1016/j.cub.2019.02.047 |issn=0960-9822 |pmid=30939303 |doi-access=free}}</ref> The resultant decrease in fish population due to warming waters has also influenced humans to see dolphins as fishing competitors or even bait. Humans use [[Dusky dolphin|dusky dolphins]] as bait or are killed off because they consume the same fish humans eat and sell for profit.<ref name=":5" /> In the central Brazilian Amazon alone, approximately 600 [[Pink River Dolphin|pink river dolphins]] are killed each year to be used as bait.<ref name=":7" /> Another side effect of increasing water temperatures is the increase in toxic [[Algal bloom|algae blooms]], which has caused a mass die-off of bottlenose dolphins.<ref name=":6" />
+== Potential effects ==
+[[Marine mammal|Marine mammals]] have evolved to live in oceans, but climate change is affecting their natural habitat.<ref name="Hardwood">{{cite journal |last=Harwood |first=John |date=1 August 2001 |title=Marine mammals and their environment in the twenty-first century |journal=Journal of Mammalogy |volume=82 |issue=3 |pages=630–640 |doi=10.1644/1545-1542(2001)082<0630:MMATEI>2.0.CO;2 |issn=0022-2372 |doi-access=free}}</ref><ref name="Simmonds">{{cite journal |last1=Simmonds |first1=Mark P. |last2=Isaac |first2=Stephen J. |date=5 March 2007 |title=The impacts of climate change on marine mammals: early signs of significant problems |journal=Oryx |volume=41 |issue=1 |pages=19–26 |doi=10.1017/s0030605307001524 |doi-access=free}}</ref><ref name="Tynan">{{cite journal |last1=Tynan |first1=Cynthia T. |last2=DeMaster |first2=Douglas P. |date=1997 |title=Observations and Predictions of Arctic Climatic Change: Potential Effects on Marine Mammals |url=http://pubs.aina.ucalgary.ca/arctic/Arctic50-4-308.pdf |journal=Arctic |volume=50 |issue=4 |pages=308–322 |doi=10.14430/arctic1113 |quote=Animals have a high risk of mortality.}}</ref><ref name="Learmonth">{{cite book |last1=Learmonth |first1=JA |title=Oceanography and marine biology an annual review. Volume 44 |last2=Macleod |first2=CD |last3=Santos |first3=MB |last4=Pierce |first4=GJ |last5=Crick |first5=HQP |last6=Robinson |first6=RA |date=2006 |publisher=Taylor & Francis |isbn=9781420006391 |editor1-last=Gibson |editor1-first=RN |location=Boca Raton |pages=431–464 |chapter=Potential effects of climate change on marine mammals |editor2-last=Atkinson |editor2-first=RJA |editor3-last=Gordon |editor3-first=JDM}}</ref> Some species may not adapt fast enough, which might lead to their extinction.<ref>{{Cite journal |last1=Laidre |first1=Kristin L. |last2=Stirling |first2=Ian |last3=Lowry |first3=Lloyd F. |last4=Wiig |first4=Øystein |last5=Heide-Jørgensen |first5=Mads Peter |last6=Ferguson |first6=Steven H. |date=January 1, 2008 |title=Quantifying the Sensitivity of Arctic Marine Mammals to Climate-Induced Habitat Change |journal=Ecological Applications |volume=18 |issue=2 |pages=S97–S125 |doi=10.1890/06-0546.1 |jstor=40062159 |pmid=18494365 |doi-access=free}}</ref>
+=== Ocean warming ===
+[[File:Increased_Trend_in_Sea_Temperature.png|thumb|The illustration of temperature changes from 1960 to 2019 across each ocean starting at the Southern Ocean around Antarctica (Cheng et. al., 2020)]]
+During the last century, the global average land and [[sea surface temperature]] has increased due to an increased greenhouse effect from human activities.<ref>[http://www.scientificamerican.com/article.cfm?id=graphic-science-map-shows-vast-regions-ocean-warmer ''Map Shows Vast Regions of Ocean Are Warmer''] March 30, 2013 [[Scientific American]]</ref> From 1960 to through 2019, the average temperature for the upper 2000 meters of the oceans has increased by 0.12 degree Celsius, whereas the ocean surface has warmed up to 1.2 degree Celsius from the pre-industrial era.<ref>{{Cite journal |last1=Cheng |first1=Lijing |last2=Abraham |first2=John |last3=Zhu |first3=Jiang |last4=Trenberth |first4=Kevin E. |last5=Fasullo |first5=John |last6=Boyer |first6=Tim |last7=Locarnini |first7=Ricardo |last8=Zhang |first8=Bin |last9=Yu |first9=Fujiang |last10=Wan |first10=Liying |last11=Chen |first11=Xingrong |date=February 2020 |title=Record-Setting Ocean Warmth Continued in 2019 |journal=Advances in Atmospheric Sciences |language=en |volume=37 |issue=2 |pages=137–142 |bibcode=2020AdAtS..37..137C |doi=10.1007/s00376-020-9283-7 |issn=0256-1530 |doi-access=free |s2cid=210157933}}</ref>
+Marine organisms usually tend to encounter relatively stable temperatures compared with terrestrial species and thus are likely to be more sensitive to temperature change than terrestrial organisms.<ref name=":1">{{Cite journal |last1=Yao |first1=Cui-Luan |last2=Somero |first2=George N. |date=February 2014 |title=The impact of ocean warming on marine organisms |url=http://link.springer.com/10.1007/s11434-014-0113-0 |journal=Chinese Science Bulletin |language=en |volume=59 |issue=5–6 |pages=468–479 |bibcode=2014ChSBu..59..468Y |doi=10.1007/s11434-014-0113-0 |issn=1001-6538 |s2cid=98449170}}</ref>  Therefore, the ocean warming will lead to increased species migration, as endangered species look for a more suitable habitat. If sea temperatures continue to rise, then some fauna may move to cooler water and some range-edge species may disappear from regional waters or experienced a reduced global range.<ref name=":1" /> Change in the abundance of some species will alter the food resources available to marine mammals, which then results in marine mammals’ biogeographic shifts. Additionally, if a species cannot successfully migrate to a suitable environment, unless it learns to adapt to rising ocean temperatures, it will face extinction.
+Sea level rise is also important when assessing the impacts of global warming on marine mammals, since it affects coastal environments that marine mammals species rely.<ref>{{cite web |last1=Glick |first1=Patrick |last2=Clough |first2=Jonathan |last3=Nunley |first3=Brad |title=Sea-Level Rise and Coastal Habitats in the Chesapeake Bay Region |url=http://www.nwf.org/pdf/Reports/FullSeaLevelRiseandCoastalHabitats_ChesapeakeRegion.pdf |access-date=November 8, 2014 |publisher=National Wildlife Federation}}</ref>
+=== Primary productivity ===
+Changes in temperatures will impact the location of areas with high [[primary productivity]]. [[Primary producer|Primary producers]], such as [[plankton]],<ref>{{cite journal |last1=Sarmento |first1=H. |last2=Montoya |first2=JM. |last3=Vázquez-Domínguez |first3=E. |last4=Vaqué |first4=D. |last5=Gasol |first5=JM. |year=2010 |title=Warming effects on marine microbial food web processes: how far can we go when it comes to predictions? |journal=Philosophical Transactions of the Royal Society B: Biological Sciences |volume=365 |issue=1549 |pages=2137–2149 |doi=10.1098/rstb.2010.0045 |pmc=2880134 |pmid=20513721}}</ref><ref>{{cite journal |last1=Vázquez-Domínguez |first1=E. |last2=Vaqué |first2=D. |last3=Gasol |first3=JM. |year=2007 |title=Ocean warming enhances respiration and carbon demand of coastal microbial plankton. |journal=Global Change Biology |volume=13 |issue=7 |pages=1327–1334 |bibcode=2007GCBio..13.1327V |doi=10.1111/j.1365-2486.2007.01377.x |hdl-access=free |hdl=10261/15731}}</ref><ref>{{cite journal |last1=Vázquez-Domínguez |first1=E. |last2=Vaqué |first2=D. |last3=Gasol |first3=JM. |year=2012 |title=Temperature effects on the heterotrophic bacteria, heterotrophic nanoflagellates, and microbial top predators of NW Mediterranean. |journal=Aquatic Microbial Ecology |volume=67 |issue=2 |pages=107–121 |doi=10.3354/ame01583 |doi-access=free}}</ref><ref>{{cite journal |last1=Mazuecos |first1=E. |last2=Arístegui |first2=J. |last3=Vázquez-Domínguez |first3=E. |last4=Ortega-Retuerta |first4=E. |last5=Gasol |first5=JM. |last6=Reche |first6=I. |year=2012 |title=Temperature control of microbial respiration and growth efficiency in the mesopelagic zone of the South Atlantic and Indian Oceans. |journal=Deep Sea Research Part I: Oceanographic Research Papers |volume=95 |issue=2 |pages=131–138 |doi=10.3354/ame01583 |doi-access=free}}</ref> are the main food source for marine mammals such as some whales. Species migration will therefore be directly affected by locations of high primary productivity. Water temperature changes also affect ocean turbulence, which has a major impact on the dispersion of plankton and other primary producers.<ref>{{cite book |last1=Castilla |first1=Juan Carlos |title=Encyclopedia of Biodiversity |publisher=Academic Press |edition=2 |pages=56–63 |chapter=Marine Ecosystems, Human Impacts on}}</ref> Due to global warming and increased glacier melt, [[thermohaline circulation]] patterns may be altered by increasing amounts of freshwater released into oceans and, therefore, changing ocean salinity. Thermohaline circulation is responsible for bringing up cold, nutrient-rich water from the depths of the ocean, a process known as [[upwelling]].<ref>{{Cite book |last=Haldar |first=Ishita |url=https://books.google.com/books?id=_k9bDwAAQBAJ&q=Thermohaline+circulation+is+responsible+for+bringing+up+cold%2C+nutrient-rich+water+from+the+depths+of+the+ocean%2C+a+process+known+as+upwelling&pg=PT28 |title=Global Warming: The Causes and Consequences |date=30 April 2018 |publisher=Readworthy |isbn=9788193534571 |language=en}}</ref>
+===Ocean acidification===
+[[File:Ocean_Acidification_under_Low_and_High_Carbon_Emission_Scenarios.png|thumb|Change in pH since the beginning of the industrial revolution. RCP 2.6 scenario is "low CO<sub>2</sub> emissions" . RCP 8.5 scenario is "high CO<sub>2</sub> emissions", the path we are currently on. Source: J. P. Gattuso et al., 2015]]
+About a quarter of the emitted CO<sub>2,</sub> about 26 million tons is absorbed by the ocean every day.<ref name=":2">{{Cite book |last=Euzen |first=Agathe |title=The ocean revealed. |publisher=CNRS ÉDITIONS |year=2017 |isbn=978-2-271-11907-0 |location=Paris}}</ref>  Consequently, the dissolution of anthropogenic carbon dioxide (CO<sub>2</sub>) in seawater causes a decrease in pH  which is corresponding to an increase in acidity of the oceans with consequences for marine biota. &nbsp;Since the beginning of the industrial revolution, ocean acidity has increased by 30% (the pH decreased from 8.2 to 8.1).<ref name=":2" /> It is projected that the ocean will experience severe acidification under RCP 8.5, high CO<sub>2</sub> emission scenario, and less intense acidification under RCP 2.6, low CO<sub>2</sub>  emission scenario. Ocean acidification will impact marine organisms (corals, mussels, oysters) in producing their limestone skeleton or shell. When CO<sub>2</sub> dissolves in seawater, it increases protons (H+ ions) but reduces certain molecules, such as carbonate ions in which many oysters needed to produce their limestone skeleton or shell.<ref name=":2" /> The shell and the skeleton of these species may become less dense or strong. This also may make coral reefs become more vulnerable to storm damage, and slow down its recovery. In addition, marine organisms may  experience changes in growth, development, abundance, and survival in response to ocean acidification.
+=== Sea ice changes ===
+Sea ice, a defining characteristic of polar marine environment, is changing rapidly which has impacts on marine mammals. Climate change models predict changes to the sea ice leading to loss of the sea ice habitat, elevations of water and air temperature, and increased occurrence of severe weather. The loss of sea ice habitat will reduced the abundance of seal prey for marine mammals, particularly polar bears. Initially, polar bears may be favored by an increase in leads in the ice that make more suitable seal habitat available but, as the ice thins further, they will have to travel more, using energy to keep in contact with favored habitat.<ref>{{Cite journal |last=Derocher |first=A. E. |date=2004-04-01 |title=Polar Bears in a Warming Climate |journal=Integrative and Comparative Biology |volume=44 |issue=2 |pages=163–176 |doi=10.1093/icb/44.2.163 |issn=1540-7063 |pmid=21680496 |doi-access=free |s2cid=13716867}}</ref>  There also may be some indirect effect of sea ice changes on animal heath due to alterations in pathogen transmission, effect on animals on body condition caused by shift in the prey based/food web, changes in toxicant exposure associated with increased human habitation in the Arctic habitat.<ref>{{Cite journal |last1=Burek |first1=Kathy A. |last2=Gulland |first2=Frances M. D. |last3=O'Hara |first3=Todd M. |date=March 2008 |title=Effects of Climate Change on Arctic Marine Mammal Health |journal=Ecological Applications |volume=18 |issue=sp2 |pages=S126–S134 |doi=10.1890/06-0553.1 |issn=1051-0761 |pmid=18494366 |doi-access=free}}</ref>
+[[File:Increased_frequency_of_Hypoxia_Occurrence_in_Baltic_sea.png|thumb|Increase frequency of Hypoxia Occurrence in the entire Baltic Sea calculated as the number of profiles with recorded hypoxia relative to the total number of profiles (Conley et. al., 2011)]]
+=== Hypoxia ===
+Hypoxia occurs in the variety of coastal environment when the dissolved of oxygen (DO) is depleted to a certain low level, where aquatic organisms, especially benthic fauna, become stressed or die due to the lack of oxygen.<ref name=":3">{{Cite journal |last1=Ekau |first1=W. |last2=Auel |first2=H. |last3=Pörtner |first3=H.-O. |last4=Gilbert |first4=D. |date=2010-05-21 |title=Impacts of hypoxia on the structure and processes in pelagic communities (zooplankton, macro-invertebrates and fish) |journal=Biogeosciences |volume=7 |issue=5 |pages=1669–1699 |bibcode=2010BGeo....7.1669E |doi=10.5194/bg-7-1669-2010 |issn=1726-4189 |doi-access=free}}</ref> Hypoxia occurs when the coastal region enhance Phosphorus release from sediment and increase Nitrate (N) loss. This chemical scenario supports favorable growth for cyanobacteria which contribute to the hypoxia and ultimately sustain eutrophication.<ref name=":4">{{Cite journal |last1=Conley |first1=Daniel J. |last2=Björck |first2=Svante |last3=Bonsdorff |first3=Erik |last4=Carstensen |first4=Jacob |last5=Destouni |first5=Georgia |last6=Gustafsson |first6=Bo G. |last7=Hietanen |first7=Susanna |last8=Kortekaas |first8=Marloes |last9=Kuosa |first9=Harri |last10=Markus Meier |first10=H. E. |last11=Müller-Karulis |first11=Baerbel |date=2009-05-15 |title=Hypoxia-Related Processes in the Baltic Sea |journal=Environmental Science & Technology |volume=43 |issue=10 |pages=3412–3420 |bibcode=2009EnST...43.3412C |doi=10.1021/es802762a |issn=0013-936X |pmid=19544833 |doi-access=free}}</ref> &nbsp;Hypoxia degrades an ecosystem by damaging the bottom fauna habitats, altering the food web, changing the nitrogen and phosphate cycling, decreasing fishery catch, and enhancing the water acidification.<ref name=":4" /> There were 500 areas in the world with reported coastal hypoxia in 2011, with Baltic Sea contains the largest hypoxia zone in the world.<ref>{{Cite journal |last1=Conley* |first1=Daniel J. |last2=Bonsdorff |first2=Erik |last3=Carstensen |first3=Jacob |last4=Destouni |first4=Georgia |last5=Gustafsson |first5=Bo G. |last6=Hansson |first6=Lars-Anders |last7=Rabalais |first7=Nancy N. |last8=Voss |first8=Maren |last9=Zillén |first9=Lovisa |date=2009-05-15 |title=Tackling Hypoxia in the Baltic Sea: Is Engineering a Solution? |journal=Environmental Science & Technology |language=en |volume=43 |issue=10 |pages=3407–3411 |bibcode=2009EnST...43.3407C |doi=10.1021/es8027633 |issn=0013-936X |pmid=19544832 |doi-access=free}}</ref> These numbers are expected to increase due to the worsening condition of coastal areas caused by the excessive anthropogenic nutrient loads that stimulate intensified eutrophication. &nbsp;The rapidly changing climate in particularly, global warming, also contributes to the increase of Hypoxia occurrence that damaging marine mammals and marine/coastal ecosystem.
+== Notes ==
+{{reflist}}
 ==See also==
@@ Line 187: / Line 244: @@
 ==External links==
 * [http://discover.itsc.uah.edu/ DISCOVER] – satellite-based ocean and climate data since 1979 from NASA
+* [http://www.mmc.gov/ Marine Mammal Commission]
+* [https://wayback.archive-it.org/all/20080510062944/http://www.unep-wcmc.org/climate/default.aspx United Nations Environment Programme World Conservation Monitoring Centre]
+{{Global warming}}
 [[Category:Effects of climate change]]
 [[Category:Oceans]]